PAEDIATRICS

Question 1

RETARDED SKELETAL MATURATION

Chronic ill-health

Answer 1

1. Congenital heart disease—particularly cyanotic.
2. Renal failure.
3. Inflammatory bowel disease*.
4. Malnutrition.
5. Rickets*.
6. Maternal deprivation.

Question 2

RETARDED SKELETAL MATURATION

Endocrine disorders

Answer 2

1. Hypothyroidism—severe retardation (≥5 standard deviations
   below the mean) with granular, fragmented epiphyses.
2. Steroid therapy/Cushing’s disease—see Part 2.
3. Hypogonadism—including older patients with Turner syndrome.
4. Hypopituitarism—panhypopituitarism, growth hormone deficiency
   and Laron dwarfism (insensitivity to growth hormone)

Question 3

RETARDED SKELETAL MATURATION

Congenital disorders

Answer 3

1. Chromosome disorders—e.g. trisomy 21, trisomy 18 (severe),
   Turner syndrome.
2. Skeletal dysplasias involving the epiphyses—e.g. multiple
   epiphyseal dysplasia, pseudoachondroplasia, diaphyseal dysplasia,
   metatropic dysplasia

Question 4

GENERALIZED ACCELERATED
SKELETAL MATURATION
Endocrine disorders

Answer 4

1. Idiopathic precocious puberty.
2. Hypothalamic dysfunction—e.g. due to mass lesions (hamartoma,
   astrocytoma, craniopharyngioma, optic chiasm glioma),
   hydrocephalus or encephalitis.
3. Adrenal and gonadal tumours—e.g. androgen-producing
   neoplasms.
4. Hyperthyroidism

Question 5

GENERALIZED ACCELERATED
SKELETAL MATURATION
Congenital disorders

Answer 5

1. McCune-Albright syndrome—polyostotic fibrous dysplasia +
   precocious puberty.
2. Cerebral gigantism (Sotos syndrome).
3. Lipodystrophy.
4. Pseudohypoparathyroidism*—premature fusion of cone-shaped
   epiphyses.
5. Acrodysostosis—premature fusion of cone-shaped epiphyses

Question 6

GENERALIZED ACCELERATED
SKELETAL MATURATION
Others

Answer 6

1. Large or obese children.

2. Familial tall stature.

Question 7

PREMATURE CLOSURE OF A

GROWTH PLATE

Answer 7

1. Local hyperaemia—juvenile idiopathic arthritides, infection,
   haemophilia or arteriovenous malformation.
2. Trauma—especially Salter-Harris fractures.
3. Vascular occlusion—postmeningococcal septicaemia, infarcts and
   sickle cell anaemia.
4. Radiotherapy.
5. Thermal injury—burns, frostbite.
6. Multiple exostoses or enchondromatosis.
7. Hypervitaminosis A—now more commonly via vitamin A
   analogue treatment for dermatological conditions rather than
   dietary overdosage.
8. Skeletal dysplasias—e.g. Albright’s hereditary osteodystrophy,
   acrodysostosis, acromesomelic dysplasia (Maroteaux type) and trichorhinophalangeal syndrome; all with premature fusion of
   cone-shaped epiphyses in the hand.
9. Iatrogenic—for leg length discrepancies surgical epiphysiodesis
   can be performed to artificially fuse or slow the growth of a
   normal leg to allow the shorter leg to grow

Question 8

ASYMMETRICAL MATURATION

Hemihypertrophy or localized gigantism

Answer 8

1. Vascular anomalies.
   (a) Parkes-Weber syndrome—fast-flow vascular malformations
   with arteriovenous shunting, port-wine stain and limb
   overgrowth.
   (b) Klippel-Trénaunay syndrome*—triad of anomalous veins
   (varicosities or slow-flow malformations), port-wine stain and
   limb overgrowth.
   (c) Capillary malformation (port-wine stain)—associated with
   congenital hypertrophy.
2. Chronic hyperaemia—e.g. juvenile idiopathic arthritides and
   haemophilia.
3. Hemihypertrophy—M>F; R>L. May be a presenting feature of
   Beckwith-Wiedemann syndrome (hemihypertrophy, macroglossia,
   hypoglycaemia and umbilical hernia). Increased risk of Wilms
   tumour.
4. Neurofibromatosis* (NF1).
5. Macrodystrophia lipomatosa—bony and fatty overgrowth of one
   or more digits.
6. Russell-Silver dwarfism—evident from birth. Triangular face with
   down-turned corners of the mouth, frontal bossing, asymmetrical
   growth and skeletal maturation.
7. Proteus syndrome—hamartomatous disorder with multiple and
   varied manifestations including vascular and lymphatic
   malformations, macrocephaly and cranial hyperostosis.
8. WAGR syndrome—Wilms tumour, aniridia, genitourinary
   anomalies and mental retardation.

Question 9

ASYMMETRICAL MATURATION

Hemiatrophy or localized atrophy

Answer 9

1. Paralysis—with osteopenia and overtubulation of long bones.
2. Radiation treatment in childhood.
3. Pure venous malformation involving skin, muscle and bone

Question 10

SKELETAL DYSPLASIAS

With predominant metaphyseal involvement

Answer 10

1. Achondroplasia*—see Part 2. NB: hypochondroplasia is due to
   mutations in the same gene, fibroblast growth factor receptor 3,
   with milder features.
2. Metaphyseal chondrodysplasias.
   (a) Jansen—severe rickets-like changes with short stature.
   (b) Schmid—milder than Jansen. Bowed legs.
   (c) McKusick—immune deficiency and haematological
   problems.
   (d) Shwachman-Diamond—with pancreatic insufficiency
   and neutropenia.
   (e) Hypophosphatasia—severe forms are lethal. V-shaped
   metaphyseal defects. Diaphyseal spurs.
   (f) Jeune’s asphyxiating thoracic dystrophy—short ribs with
   irregular costochondral junctions, renal cysts and short hands.
   (g) Ellis-van Creveld syndrome—short ribs with congenital heart
   disease and polydactyly.

Question 11

SKELETAL DYSPLASIAS
With predominant epiphyseal involvement
3

Answer 11

1. Multiple epiphyseal dysplasia—irregular epiphyseal ossification.
   Epiphyses may be small and round or flat, depending on type.
   Normal metaphyses, mild spine changes, mild short stature.
2. Pseudoachondroplasia—more severe epiphyseal dysplasia with short stature; proportions resemble achondroplasia but with a normal face. Spinal radiographic changes, but usually preserved spinal height.
3. Diastrophic dysplasia—flattened epiphyses with joint contractures
   (e.g. club feet) and kyphoscoliosis. Cauliflower ear in infancy.
   Hypoplastic proximally placed ‘hitch-hiker’s’ thumb is characteristic

Question 12

SKELETAL DYSPLASIAS
Mesomelic dysplasias (short forearms ± shanks)

Answer 12

1. Dyschondrosteosis (Leri-Weill)—short radius + Madelung
   deformity and dorsal subluxation of distal ulna.
2. Langer mesomelic dysplasia—more severe mesomelic
   shortening.
3. Acromesomelic dysplasia (Maroteaux type)—short upper limbs
   with shortening more severe from distal to proximal. Associated
   spinal abnormalities

Question 13

SKELETAL DYSPLASIAS
Acromelic dysplasias (short hands and feet) 4

Answer 13

1. Pseudo- and pseudopseudo-hypoparathyroidism—metacarpal ±
   phalangeal shortening. Soft-tissue/basal ganglia calcifications and
   exostoses in some.
2. Brachydactyly types A–E—abnormal hands and feet only.
3. Acrodysostosis—very short metacarpals and phalanges with cone
   epiphyses. Similar to acromesomelic dysplasia on imaging.
4. Trichorhinophalangeal syndrome—multiple short phalanges with
   cone epiphyses. Sparse hair and typical facial appearances. Type 2
   associated with exostoses

Question 14

SKELETAL DYSPLASIAS
Dysplasias with major involvement of the spine
2

Answer 14

1. Type 2 collagen disorders
   includes spondyloepiphyseal dysplasia congenita, Kniest and Stickler type 1. Delayed appearance of epiphyseal ossification centres with progressive platyspondyly and spinal deformity. Associated ear and eye problems and micrognathia in many. Hands and feet near normal.
2. Metatropic dysplasia—‘changing form’.
   In infancy manifests as short-limbed dysplasia, evolving into short spine dysplasia over childhood. Epiphyseal ossification delay with marked metaphyseal flare. Characteristic pattern of platyspondyly with wide flat
   vertebral bodies. Some patients have a tail. Spondylometaphyseal
   dysplasia (Kozlowski type) is a milder form.

Question 15

LETHAL NEONATAL DYSPLASIA

Answer 15

1. Thanatophoric dysplasia—short ribs; severe platyspondyly with
   wafer-thin vertebral bodies; small square iliac wings; severe limb
   shortening. Curved femora and humeri (‘telephone handle’) in
   type 1; craniosynostosis in type 2.
2. Osteogenesis imperfecta type 2—deficient skull ossification;
   numerous fractures resulting in crumpled long bones and
   beaded ribs.
3. Achondrogenesis—absent or poor ossification, especially of
   vertebral bodies; small chest; very short long bones.
4. Hypochondrogenesis—milder form of achondrogenesis, but still
   lethal.
5. Short rib polydactyly syndromes—extremely short ribs;
   polydactyly in most with variable acromesomelic shortening
   depending on type.
6. Fibrochondrogenesis—short long bones with metaphyseal flaring
   and diamond-shaped vertebrae.
7. Campomelic dysplasia—bowed femora and tibiae. Deficient
   ossification of thoracic pedicles and severe hypoplasia of scapular
   blades are most characteristic features. Eleven ribs.
8. Chondrodysplasia punctata—see Section 14.15.
9. Lethal hypophosphatasia—severely deficient skull ossification.
   Absent pedicles in spine. Missing bones. Variable metaphyseal
   defects. Some bones look normal.

Question 16

CONDITIONS EXHIBITING
DYSOSTOSIS MULTIPLEX
dysostosis refers to abnormal 
bone formation in early pregnancy and the distribution of 
involved bones remains static

Answer 16

(a) Abnormal bone texture.
(b) Large skull vault with calvarial thickening.
(c) J-shaped sella + poor pneumatization of paranasal sinuses.
(d) Odontoid hypoplasia + atlantoaxial subluxation.
(e) Anterior beak of upper lumbar vertebrae + gibbus deformity.
(f) Inferior tapering of iliac bones + steep acetabula + coxa valga.
(g) Widened diaphyses, e.g. ribs (oar-shaped), clavicles, small
tubular bones.
(h) Tilting of distal radius and ulna towards each other.
(i) Pointing of the proximal ends of the metacarpals

Question 17

Diseases exhibiting dysostosis multiplex

rare disease of congenital origin characterized by chondrodystrophic skeletal changes and deposition of a lipid-like substance

6

Answer 17

1. Mucopolysaccharidoses.
2. Mucolipidoses types I–III.
3. Fucosidosis types I and II.
4. GM1 gangliosidosis.
5. Mannosidosis.
6. Aspartylglucosaminuria

Superiorly notched [inferiorly beaked] vertebral bodies
Middle beaked in MPS I
Posterior scalloping
Rounded iliac wings
Ilia, tapered inferiorly
Abnormal J-shaped sella
Thickened diploic space
Short, thick clavicles
Paddle [oar-shaped] ribs
Mildly hypoplastic epiphyses [often generalized]
 Long/narrow femoral neck
 Hypoplastic/fragmented CFE
Thick [short] diaphyses
Proximal humeral notching
Metacarpals: Proximal pointing
 Metacarpals: Thick, short, with thin cortices
 Carpal bones: Irregular, hypoplastic
 Tarsal bones: Irregular contours

Question 18

GENERALIZED INCREASED BONE DENSITY

Dysplasias

Answer 18

1. Osteopetrosis—diffuse bony sclerosis due to reduced osteoclast
   activity, with a ‘bone-in-bone’ appearance and ‘rugger jersey’
   spine. Increase risk of fractures.
2. Pyknodysostosis—short stature, hypoplastic lateral ends of
   clavicles, hypoplastic terminal phalanges, bulging cranium and
   delayed closure of the anterior fontanelle.
3. Dysosteosclerosis—thought to be an osteoclast-poor form of
   osteopetrosis in infancy, but does not cause ‘bone-in-bone’
   appearance. Progressive spinal involvement with endplate
   irregularity, and marked undertubulation of long bones with
   submetaphyseal lucencies.
4. Progressive diaphyseal dysplasia (Camurati-Engelmann
   syndrome)—diffuse symmetrical cortical thickening in diaphyses
   of long bones (especially femur and tibia) ± skull or spine
   involvement.
5. Melorheostosis—undulating periosteal ± endosteal hyperostosis
   with a characteristic ‘dripping candle wax’ appearance. Involves
   one or more bones in a single limb, in a sclerotomal distribution.
6. Wnt-pathway disorders—including endosteal hyperostosis,
   hyperostosis corticalis generalisata, sclerosteosis and osteopathia
   striata

Question 19

GENERALIZED INCREASED BONE DENSITY

Metabolic

Answer 19

1. Renal osteodystrophy*—rarely renal osteodystrophy causes bone
   sclerosis, typically seen as a ‘rugger jersey’ spine. Oxalosis may also
   cause renal failure and bone sclerosis

Question 20

GENERALIZED INCREASED BONE DENSITY paediatrics
Poisoning
4

Answer 20

1. Lead—dense metaphyseal bands. Cortex and flat bones may also
   be slightly dense. Modelling deformities later, e.g. flask-shaped femora.
2. Fluorosis—more common in adults. Thickened cortex at the
   expense of the medulla. Periosteal reaction. Ossification of
   ligaments, tendons and interosseous membranes.
3. Hypervitaminosis D—slightly increased density of skull and
   vertebrae early, followed later by osteoporosis. Soft-tissuecalcification. Dense metaphyseal bands and widened zone of provisional calcification.
4. Chronic hypervitaminosis A—not <1 year of age. Cortical
   thickening of long and tubular bones, especially in the feet.
   Subperiosteal new bone. Normal epiphyses, reduced metaphyseal
   density. The mandible is not affected (cf. Caffey’s disease)

Question 21

GENERALIZED INCREASED BONE DENSITY

Idiopathic

Answer 21

1. Caffey’s disease (infantile cortical hyperostosis)—see Section 14.11.
2. Idiopathic hypercalcaemia of infancy—probably a manifestation
   of hypervitaminosis D. Generalized increased density or dense
   metaphyseal bands. Increased density of skull base.

Question 22

PAEDIATRIC TUMOURS THAT METASTASIZE TO BONE

Answer 22

1. Neuroblastoma.
2. Leukaemia.
3. Lymphoma*.
4. Renal clear cell sarcoma.
5. Rhabdomyosarcoma.
6. Retinoblastoma.
7. Ewing sarcoma—lung metastases much more common.
8. Osteosarcoma—lung metastases much more common

Question 23

‘MOTH-EATEN BONE’ IN A CHILD

Neoplastic

Answer 23

1. Neuroblastoma metastases.
2. Leukaemia—consider when there is diffuse involvement of an
   entire bone or a neighbouring bone with low T1 and high T2/STIR
   signal on MRI.
3. Long bone sarcomas—Ewing sarcoma and osteosarcoma.
4. Lymphoma of bone.
5. Langerhans cell histiocytosis (LCH)*.

Question 24

‘MOTH-EATEN BONE’ IN A CHILD

Infective

Answer 24

1. Acute osteomyelitis

Question 25

PERIOSTEAL REACTIONS—BILATERALLY

SYMMETRICAL IN CHILDREN

Answer 25

1. Normal infants—diaphyseal, not extending to the growth plate,
   bilaterally symmetrical and a single lamina. Frequently involves
   femur, tibia and humerus. Very unusual >4 months of age. A
   mimicker of trauma; sometimes difficult to differentiate from child
   abuse when seen incidentally on skeletal survey.
2. Juvenile idiopathic arthritis*—in ~25% of cases. Most common in
   the periarticular regions of phalanges, metacarpals and metatarsals.
   When it extends into the diaphysis it will eventually result in
   enlarged, rectangular tubular bones.
3. Acute leukaemia—associated with prominent metaphyseal bone
   resorption ± a dense zone of provisional calcification. Osteopenia.
   Metastatic neuroblastoma can look identical.
4. Rickets*—the presence of uncalcified subperiosteal osteoid mimics
   a periosteal reaction because the periosteum and ossified cortex
   are separated.
5. Caffey’s disease—first evident <5 months of age. Mandible,
   clavicles and ribs show cortical hyperostosis and a diffuse periosteal
   reaction. The scapulae and tubular bones are affected less often
   and tend to be involved asymmetrically.
6. Scurvy*—subperiosteal haemorrhage is most frequent in the
   femur, tibia and humerus. Periosteal reaction is particularly evident
   in the healing phase. Age ≥6 months.
7. Prostaglandin E1 therapy—in infants with ductus-dependent
   congenital heart disease. Severity is related to duration of therapy.
   Other features include pseudowidening of cranial sutures and
   bone-in-bone appearance.
8. Congenital syphilis*—an exuberant periosteal reaction can be due
   to infiltration by syphilitic granulation tissue (diaphyseal) or healing
   of osteochondritis by callus (metaphyseal-epiphyseal junction)

Question 26

SYNDROMES AND BONE DYSPLASIAS
FEATURING MULTIPLE FRACTURES
With reduced bone density

Answer 26

1. Osteogenesis imperfecta.
2. Rickets*—usually only in presence of severe rachitic change and
   clear demineralization.
3. Hypophosphatasia.
4. Juvenile idiopathic osteoporosis—2–4 years duration, age of
   onset 2–13 years.
5. Gerodermia osteodysplastica—osteopenia and wormian bones
   associated with wrinkly skin (cutis laxa) and hip dislocation.
6. Osteoporosis-pseudoglioma syndrome—blindness in infancy +
   bony fragility.
7. Mucolipidosis II—osteopenia and periosteal ‘cloaking’ in infancy,
   evolving into dysostosis multiplex.
8. Cushing’s syndrome.

Question 27

SYNDROMES AND BONE DYSPLASIAS
FEATURING MULTIPLE FRACTURES
With normal bone density
2

Answer 27

1. Cleidocranial dysplasia( absent/hypoplastic clavicles; widened sutures, brachycephaly,, maxilla/max sinus hypoplasia, wormian bones, supernumery teeth).
2. Fibrous dysplasia.

Question 28

SYNDROMES AND BONE DYSPLASIAS
FEATURING MULTIPLE FRACTURES
With increased bone density

Answer 28

1. Osteopetrosis.

2. Pyknodysostosis

Question 29

PSEUDARTHROSIS IN A CHILD 7

Answer 29

1. Nonunion of a fracture—including pathological fracture.
2. Congenital—in the mid-lower third of the tibia ± fibula. 50%
   present in the first year. Later there may be cupping of the
   proximal bone end and pointing of the distal bone end.
3. Neurofibromatosis*—identical to congenital tibial pseudarthrosis.
4. Osteogenesis imperfecta.
5. Cleidocranial dysplasia*—congenitally in the femur.
6. Fibrous dysplasia.
7. Proximal focal femoral deficiency—at the site of the femoral
   defect

Question 30

‘BONE WITHIN A BONE’ APPEARANCE 8

Answer 30

1. Normal neonate—especially in the spine.
2. Growth arrest/recovery lines.
3. Bisphosphonate therapy—similar to growth arrest lines.
4. Osteopetrosis.
5. Sickle cell anaemia.
6. Gaucher disease*.
7. Heavy metal poisoning.
8. Prostaglandin E1 therapy

Question 31

IRREGULAR OR STIPPLED EPIPHYSES 11

Answer 31

1. Normal—particularly in the distal femur.
2. Avascular necrosis—single, e.g. Perthes’ disease (although 10% are bilateral), or multiple, e.g. sickle cell anaemia.
3. Congenital hypothyroidism—not present at birth. Delayed appearance and growth of ossification centres. Appearance varies from slightly granular to fragmentation. The femoral capital epiphysis may be divided into inner and outer halves.
4. Morquio syndrome—irregular ossification of the femoral capital epiphyses results in flattening.
5. Multiple epiphyseal dysplasia
6. Meyer dysplasia—resembles multiple epiphyseal dysplasia but limited to the femoral heads.
7. Chondrodysplasia punctata—punctate calcifications of developing epiphyses in fetus and infant which resolve in first few years of life, with disturbance of growth of affected bones. Cause may be genetic or maternal during pregnancy (e.g. mixed connective tissue disease, hyperemesis gravidarum, vitamin K deficiency and warfarin embryopathy).
8. Trisomy 18 and 21.
9. Prenatal infections.
10. Zellweger syndrome (cerebrohepatorenal syndrome).
11. Fetal alcohol syndrome—mostly calcaneum and lower extremities

Question 32

SOLITARY RADIOLUCENT

METAPHYSEAL BAND 8

Answer 32

1. Normal neonate.
2. Any severe illness.
3. Metaphyseal fracture—especially in nonaccidental injury.
   Depending on the radiographic projection there may be the
   additional appearance of a ‘corner’ or ‘bucket-handle’ fracture.
4. Healing rickets*.
5. Leukaemia, lymphoma* or metastatic neuroblastoma.
6. Congenital infections.
7. Intrauterine perforation.
8. Scurvy*

Question 33

ALTERNATING RADIOLUCENT AND

DENSE METAPHYSEAL BANDS 7

Answer 33

1. Growth arrest lines—Harris or Park lines.
2. Bisphosphonate therapy—‘zebra stripes’ appearance.
3. Rickets*—especially those types that require prolonged treatment
   such as vitamin D-dependent rickets.
4. Osteopetrosis.
5. Chemotherapy.
6. Chronic anaemias—sickle cell and thalassaemia.
7. Treated leukaemia

Question 34

SOLITARY DENSE METAPHYSEAL BAND 6

Answer 34

1. Normal infants.
2. Lead poisoning—dense line in the proximal fibula is said to
   differentiate from normal. Other poisons include bismuth, arsenic,
   phosphorus, mercury fluoride and radium.
3. Radiation.
4. Congenital hypothyroidism.
5. Osteopetrosis.
6. Hypervitaminosis D.

Question 35

DENSE VERTICAL METAPHYSEAL LINES 4

Answer 35

1. Congenital rubella—celery stalk appearance. Less commonly in 
congenital CMV.
2. Osteopathia striata—± exostoses.
3. Hypophosphatasia.
4. Localized metaphyseal injury

Question 36

FRAYING OF METAPHYSES 4

Answer 36

1. Rickets*.
2. Hypophosphatasia—similar features as rickets.
3. Chronic stress—in the wrists of young gymnasts; wide, irregular,
   asymmetrical widening of the distal radial growth plate and
   metaphyseal sclerosis.
4. Copper deficiency

Question 37

CUPPING OF METAPHYSES 6

Answer 37

1. Normal—especially distal ulna and proximal fibula of young
   children. No fraying.
2. Rickets*—with widening of the growth plate and fraying.
3. Trauma—to the growth plate/metaphysis. Localized changes.
4. Bone dysplasias—e.g. achondroplasia, pseudoachondroplasia,
   metatropic dwarfism, diastrophic dwarfism, the metaphyseal
   chondrodysplasias, hypophosphatasia.
5. Scurvy*—usually after fracture.
6. Menkes disease—Copper deficiency can have similar appearances

Question 38

ERLENMEYER FLASK DEFORMITY

Dysplasias 3

Answer 38

1. Osteopetrosis—in infantile and juvenile forms. Particularly striking
   in the similar disorder of dysosteosclerosis.
2. Craniotubular disorders—e.g. metaphyseal dysplasia,
   craniometaphyseal dysplasia, craniodiaphyseal dysplasia,
   progressive diaphyseal dysplasia.
3. Others—otopalatodigital syndrome type 1, Melnick-Needles
   syndrome and frontometaphyseal dysplasia

Question 39

ERLENMEYER FLASK DEFORMITY

Haematological 1

Answer 39

1. Thalassaemia*.

Question 40

ERLENMEYER FLASK DEFORMITY

Depositional disorders 2

Answer 40

. Gaucher disease*.

2. Niemann-Pick disease*.

Question 41

ERLENMEYER FLASK DEFORMITY

Poisoning 1

Answer 41

1. Lead poisoning—thick transverse dense metaphyseal bands are
   the classic manifestation of chronic infantile and juvenile lead
   poisoning. There may also be flask-shaped femora, which can
   persist for years before resolving

Question 42

FOCAL RIB LESION (SOLITARY OR
MULTIPLE) IN A CHILD
Neoplastic 4

Answer 42

1. Metastases—typically neuroblastoma.
2. Ewing sarcoma—can arise from bone or chest wall (Askin
   tumour) .
3. Benign—e.g. osteochondroma, enchondroma.
4. Langerhans cell histiocytosis*.

Question 43

FOCAL RIB LESION (SOLITARY OR
MULTIPLE) IN A CHILD
Nonneoplastic 3

Answer 43

1. Healed rib fracture.
2. Fibrous dysplasia.
3. Osteomyelitis—bacterial, tuberculous or fungal.

Question 44

WIDENING OF THE SYMPHYSIS PUBIS
>10 mm in the newborn, >9 mm at 3 years, >8 mm at 7 years and
over.
Acquired 2

Answer 44

1. Trauma.

2. Infection—low-grade osteomyelitis mimics osteitis pubis

Question 45

WIDENING OF THE SYMPHYSIS PUBIS

With normal ossification 9

Answer 45

1. Bladder exstrophy—marked widening; ‘manta ray’ sign.
2. Cloacal exstrophy
3. Epispadias—degree of widening correlates well with severity of
   epispadias.
4. Hypospadias.
5. Imperforate anus with rectovaginal fistula.
6. Urethral duplication.
7. Prune-belly syndrome. ( partial or complete absence of the abdominal muscles, bilateral cryptorchidism and/or urinary tract malformations.)
8. Sjögren–Larsson syndrome. ( is an inherited disorder characterized by scaling skin (ichthyosis), intellectual disability, speech abnormalities, and spasticity. Affected infants develop various degrees of reddened skin with fine scales soon after birth)
9. Goltz syndrome (It is a type of ectodermal dysplasia, a group of heritable disorders causing the hair, teeth, nails, and glands to develop and function abnormally.)

Question 46

WIDENING OF THE SYMPHYSIS PUBIS

Poorly ossified cartilage 12

Answer 46

1. Cleidocranial dysplasia*.
2. Achondrogenesis/hypochondrogenesis.
3. Campomelic dysplasia.
4. Chondrodysplasia punctata.
5. Hypophosphatasia.
6. Congenital hypothyroidism.
7. Spondyloepiphyseal dysplasia congenita.
8. Spondyloepimetaphyseal dysplasia.
9. Pyknodysostosis.
10. Larsen syndrome.
11. Wolf-Hirschhorn syndrome.
12. Chromosome 9(p+) trisomy syndrome

Question 47

‘SHEETS’ OF CALCIFICATION IN

A CHILD 2

Answer 47

1. Fibrodysplasia ossificans progressiva—manifests in childhood.
   Initially neck and trunk muscles involved. Short first metacarpal
   and metatarsal.
2. Juvenile dermatomyositis

Question 48

PLATYSPONDYLY IN CHILDHOOD

Congenital platyspondyly 4

Answer 48

1. Thanatophoric dwarfism—inverted ‘U’- or ‘H’-shaped vertebrae
   with markedly increased disc space/body height ratio. Telephone
   handle-shaped long bones.
2. Metatropic dwarfism—flat-appearing vertebral bodies, but large
   disc spaces mean that overall spinal height is near normal in
   infancy. As childhood progresses, relative spinal height reduces.
3. Osteogenesis imperfecta—type IIA.
4. Homozygous achondroplasia

Question 49

PLATYSPONDYLY IN CHILDHOOD

Platyspondyly in later childhood 3

Answer 49

1. Morquio syndrome.
2. Spondyloepiphyseal dysplasia congenita/tarda.
3. Kniest syndrome.

Question 50

PLATYSPONDYLY IN CHILDHOOD

Acquired platyspondyly 4

Answer 50

1. Scheuermann’s disease—irregular endplates and Schmorl’s nodes
   in the thoracic spine of children and young adults. Disc-space
   narrowing. May progress to a severe kyphosis.
2. Langerhans cell histiocytosis*—the spine is more frequently
   involved in eosinophilic granuloma and Hand-Schüller-Christian
   disease than in Letterer-Siwe disease. The thoracic and lumbosacral
   spine are the usual sites of disease. Disc spaces are preserved.
3. Osteogenesis imperfecta—multiple spinal compression fractures,
   resulting in loss of height and spinal deformity.
4. Sickle cell anaemia—characteristic step-like depression in the
   central part of the endplates (‘H-shaped’ vertebrae).

Question 51

ANTERIOR VERTEBRAL BODY BEAKS
7
Involves 1–3 vertebral bodies at the thoracolumbar junction,
usually associated with a kyphosis. Hypotonia is probably the
common denominator, leading to an exaggerated thoracolumbar
kyphosis, anterior herniation of the nucleus pulposus and
subsequently an anterior vertebral body defect

Answer 51

1. Mucopolysaccharidoses*—with platyspondyly in Morquio; this is
   probably a more useful distinguishing characteristic than the
   position of the beak (inferior or middle), which is variable.
2. Achondroplasia*.
3. Mucolipidoses.
4. Pseudoachondroplasia.
5. Congenital hypothyroidism.
6. Down’s syndrome*.
7. Neuromuscular diseases

Question 52

MULTIFOCAL BONE MARROW LESIONS
ON MRI
Malignancy 2

Answer 52

. Metastases—commonly from neuroblastoma, leukaemia,
lymphoma, clear cell sarcoma, rhabdomyosarcoma, retinoblastoma,
osteosarcoma and Ewing sarcoma
2. Langerhans cell histiocytosis*—low T1 signal, high signal on T2
fatsat sequences, variable enhancement pattern

Question 53

MULTIFOCAL BONE MARROW LESIONS
ON MRI
Dysplasias 3

Answer 53

1. Hereditary multiple osteochondromas.
2. Enchondromatosis.
3. Polyostotic fibrous dysplasia—isointense with focal low signal
   areas on T1, heterogeneous on T2, patchy variable enhancement

Question 54

MULTIFOCAL BONE MARROW LESIONS
ON MRI
Infection/inflammatory 2

Answer 54

1. Multifocal osteomyelitis—may present with nonenhancing fluid
   collections and rim-enhancing abscesses in bone, joint effusions
   and cartilaginous involvement.
2. Chronic recurrent multifocal osteomyelitis—idiopathic,
   noninfective, inflammatory disorder. Diagnosis of exclusion. Tends
   to occur at epiphyseal/metaphyseal regions in long bones,
   especially the clavicles (rare for haematogenous osteomyelitis)

Question 55

MULTIFOCAL BONE MARROW LESIONS
ON MRI
Trauma/infarction
2

Answer 55

1. Multiple stress fractures—as seen in gymnasts and young athletes
   from repetitive strain.
2. Multifocal infarction/avascular necrosis—children prone to this
   include those with sickle cell disease, corticosteroid exposure,
   storage disorders and inflammatory arthritis. May also occur
   secondary to radiotherapy

Question 56

SOFT-TISSUE TUMOURS AND MASSES

Vascular tumours
3

Answer 56

1. Infantile haemangioma—usually solitary, first noticed around time
   of birth with a period of proliferation before involution (90% will
   have involuted by 9 years).
2. Congenital haemangioma—similar appearance to infantile type,
   but does not grow after birth; depending on subtype they can
   involute. RICH, PICH, NICH
3. Kaposiform haemangioendothelioma—associated with
   Kasabach-Merritt syndrome ( thrombocytopenia, coagulopathy)

Question 57

SOFT-TISSUE TUMOURS AND MASSES
Vascular malformations (can also occur in
combination with each other) 4

Answer 57

1. Arteriovenous malformation—high flow lesion, 60% are
   diagnosed at birth.
2. Venous malformations—low flow lesion, phleboliths commonly
   present.
3. Lymphatic malformation—previously referred to as cystic
   hygromas.
4. Capillary malformations—usually do not require imaging to
   diagnose

Question 58

SOFT-TISSUE TUMOURS AND MASSES

Fat-containing soft-tissue lesions 6

Answer 58

1. Lipoma—usually no vascularity, can have a fibrous capsule that
   may enhance, but should not internally enhance on MRI.
   Uncommon in children.
2. Lipoblastoma—benign tumour, exclusively found within first 3
   years of life. Slightly lower T1 signal compared to normal fat.
3. Angiolipoma—slow growing, painful, ± vascular flow (in 25%).
4. Lipomatosis—infiltrative adipose tissue involving multiple layers
   (muscle, skin and bone). Usually <2 years of age.
5. Fibrous hamartoma of infancy (FHI)—>90% occur in infancy,
   most common around shoulder or inguinal region. Subcutaneous
   location. Contains fat and T1/T2 hypointense strands of fibrous
   tissue.
6. Lipofibromatosis—benign tumour of young children, most
   common in hands and feet (in contrast to FHI). Contains fat and
   fibrous tissue, often infiltrative

Question 59

SOFT-TISSUE TUMOURS AND MASSES

Fibrous soft-tissue lesions 13

Answer 59

1. Rhabdomyosarcoma—most common soft-tissue sarcoma in
   children. Can occur anywhere (not just in skeletal muscle), e.g.
   orbit, pharynx, sinuses, paratesticular, bladder, etc. Nonspecific
   imaging features.
2. Synovial sarcoma—usually in adolescents, most commonly in
   soft tissues near the knees. Calcification, if present, is suggestive.
3. Infantile myofibroma—typically <2 years of age. Benign, usually
   solitary and subcutaneous, but can be multiple (myofibromatosis)
   and deep, involving muscle, bone or viscera (the latter is rare and
   conveys a poor prognosis). Bone lesions are typically metaphyseal
   and well-defined. Often regresses spontaneously if viscera are not
   involved.
4. Fibrous hamartoma of infancy—contains fat; see above.
5. Lipofibromatosis—contains fat; see above.
6. Nodular fasciitis—see Section 4.4. Can occur in children, usually
   adolescents (except cranial fasciitis that occurs <2 years of age)
7. Desmoid tumour—see Section 4.4. May be the first sign of
   Gardner syndrome (‘Gardner fibroma’).
8. Inflammatory pseudotumour—can occur anywhere, most
   commonly lung, mesentery and omentum. Variable imaging
   appearance.
9. Fibromatosis colli—<6 months of age, benign fibroblastic
   proliferation specific to the sternocleidomastoid muscle. Unilateral
   fusiform muscle thickening is characteristic.
10. Fibroma of tendon sheath—typically involves tendons of the
    hands. T2 hypointense, no/minimal enhancement.
11. Infantile digital fibroma—<3 years of age, subcutaneous nodule
    in dorsolateral aspect of digits.
12. Infantile fibrosarcoma—typically <2 years of age. Large painless
    mass, rapid growth. Heterogeneous and hypervascular on US/
    MRI, can cause adjacent bone erosion.
13. Low-grade fibromyxoid sarcoma—can occur in children.
    Alternating T2 hyper- and hypointense areas due to mixture of
    myxoid and fibrous components.

Question 60

SOFT-TISSUE TUMOURS AND MASSES

Soft-tissue tumour mimics 4

Answer 60

1. Posttraumatic lesions—e.g. contusion, fat necrosis, foreign body
   reaction or cellulitis. Typically painful and ill-defined on imaging.
2. Subcutaneous granuloma annulare—rapidly growing painless
   subcutaneous nodule, typically in children <5 years of age. Most
   common on extensor surface of extremities (especially pretibial) or
   in scalp. Nonspecific ill-defined lesion on US/MRI. Resolves
   spontaneously.
3. Pilomatricoma—often calcified; see Section 4.2.
4. Microcystic lymphatic malformation—appears solid on US ±
   enhancement on MRI.

Question 61

OSTEOCHONDRITIS DISSECANS

OSTEOCHONDRAL DEFECTS

Answer 61

• Multiple adjacent bone cysts at margin of defect, or a single cyst
>5 mm
• Fluid separating bone fragment from adjacent bone (fluid rim)
• Multiple disruptions in subchondral plate

Common locations
• Arms: capitellum of humerus, radial head.
• Legs: anteromedial talar dome, lateral aspect of medial femoral
condyle.

Question 62

ACUTE UPPER AIRWAY OBSTRUCTION IN

A CHILD 7

Answer 62

1. Laryngotracheobronchitis (croup)—most common 6 months–3
   years. Narrowing of the glottic and subglottic airway. Ballooning of
   hypopharynx on lateral view. ‘Steepling’ of upper airway on frontal
   view.
2. Acute epiglottitis—the epiglottis is swollen ± shortened. Other
   components of the supraglottic region (aryepiglottic folds,
   arytenoids, uvula and prevertebral soft tissues) are also swollen.
   The hypopharynx and pyriform sinuses are distended with air.
3. Abscess—retropharyngeal is more common <2 years as
   retropharyngeal nodes atrophy thereafter. Enlarged prevertebral
   soft tissues ± gas or air-fluid level. Rim enhancement seen post
   contrast on CT or MRI. Role for US in diagnosis and follow-up.
   Peritonsillar is more common in teenagers and young adults.
4. Oedema—caused by angioedema (allergic, anaphylactic or
   hereditary), inhalation of noxious gases or trauma. Predominantly
   laryngeal oedema.
5. Foreign body—more commonly occludes a major bronchus rather
   than the upper airway.
6. Choanal atresia—most common congenital nasal abnormality;
   bilateral (33%) or unilateral (R>L), bony (90%) or membranous,
   complete or incomplete. When bilateral and complete, it presents
   with severe respiratory distress at birth (infants are primarily nasal
   breathers until 6 weeks–6 months of age). Incomplete obstruction
   is associated with respiratory difficulty during feeding. Diagnosis is
   determined by failure to pass a catheter through the nose,
   nasopharyngography or CT.
7. Retropharyngeal haemorrhage—due to trauma, neck surgery,
   direct carotid arteriography or bleeding disorders. Widened
   retropharyngeal soft-tissue space

Question 63

CHRONIC UPPER AIRWAY
OBSTRUCTION IN A CHILD
Nasal 3

Answer 63

1. Choanal atresia—see Section 14.33.
2. Juvenile nasopharyngeal angiofibroma—nearly always in
   adolescent males. Symptoms of nasal obstruction and/or recurrent
   atraumatic epistaxis. Benign but locally aggressive, causing bony
   remodelling. Avid enhancement on CT/MRI. Plain films may show:
   (a) Anterior bowing of the posterior wall of the maxillary antrum.
   (b) Deviation of the nasal septum.
   (c) A nasopharyngeal soft-tissue mass with erosion of contiguous
   bony structures.
3. Antrochoanal polyp.

Question 64

CHRONIC UPPER AIRWAY
OBSTRUCTION IN A CHILD
Supraglottic 4

Answer 64

1. Grossly enlarged tonsils and adenoids.
2. Laryngomalacia—presents at or shortly after birth, persists for
   several months and usually resolves by 2 years. Diagnosis is
   confirmed by direct laryngoscopy, but fluoroscopy reveals anterior
   motion of aryepiglottic folds and distension of hypopharynx.
3. Micrognathia—e.g. in Pierre Robin syndrome.
4. Cysts—of the epiglottis or aryepiglottic folds. The degree of
   obstruction depends on size and location

Question 65

CHRONIC UPPER AIRWAY
OBSTRUCTION IN A CHILD
Glottic 1

Answer 65

1. Laryngeal polyp, papilloma or cyst

Question 66

CHRONIC UPPER AIRWAY
OBSTRUCTION IN A CHILD
Subglottic and tracheal 7

Answer 66

1. Tracheomalacia—weakness of tracheal wall, may be:
   (a) Primary—e.g. premature infants; also in cartilage disorders, e.g. polychondritis, chondromalacia, mucopolysaccharidoses.
   (b) Secondary.
   (i) Following prolonged intubation.
   (ii) With tracheoesophageal fistula/oesophageal atresia.
   (iii) With vascular ring or other extrinsic vascular compression.
   (iv) With long-standing external compression by tumour, etc.
2. Vascular ring.
   (a) Double aortic arch.
   (b) Right arch with left-sided duct/ductal ligament.
   (c) Pulmonary artery sling—often coexists with intrinsic airway
   narrowing from complete cartilage rings.
   (d) Anomalous subclavian artery ± large Kommerell diverticulum ( bulbous configuration of the origin of an aberrant left subclavian artery in the setting of a right-sided aortic arch.)
3. Following prolonged inflammation—e.g. prolonged tracheal intubation (may be fixed stenosis or malacia) or chronic aspiration (laryngeal cleft, H-type tracheoesophageal fistula, etc.).
4. External compression from other structures—e.g. adenopathy, foregut duplication cyst, teratoma, lymphovascular malformation, enlarged heart or pulmonary trunk (especially in tetralogy of Fallot with absent pulmonary valve or severe pulmonary hypertension).
5. Subglottic haemangioma—the most common subglottic soft-tissue mass in infancy. Occurs <6 months. 50% have associated cutaneous haemangiomas. Characteristically produces an asymmetrical narrowing of the subglottic airway.
6. Intrinsic congenital obstruction—e.g. tracheal stenosis due to complete cartilage rings, webs, etc. Can result in congenital high airway obstruction syndrome (CHAOS).
7. Respiratory papillomatosis—occurs anywhere from the nose to the lungs; most cases are limited to the larynx. Irregular soft-tissue masses ± cavitation of lung lesions.

Question 67

NEONATAL RESPIRATORY DISTRESS
Pulmonary causes With no mediastinal shift
8

Answer 67

1. Respiratory distress syndrome (RDS)—surfactant deficiency
   disorder, occurs in premature infants. Symptomatic soon after birth
   but maximum radiographic findings develop at 12–14 hours. Fine
   granular pattern throughout both lungs, air bronchograms, and
   later, obscured heart and diaphragm outlines. Small lung volumes
   due to diffuse microatelectasis. Often cardiomegaly. May progress
   to a complete ‘white-out’. Frequent ventilator-associated
   complications include pulmonary interstitial emphysema,
   pneumomediastinum and pneumothorax, all of which can lead to
   mediastinal displacement. Patchy clearing of infiltrate occurs after
   exogenous surfactant therapy. As oxygenation improves,
   bidirectional or left-to-right shunting through the patent ductus
   arteriosus may lead to pulmonary oedema, cardiomegaly and
   occasionally pulmonary haemorrhage
2. Transient tachypnoea of the newborn (TTN)—prominent
   interstitial markings and vessels, thickened septa, small effusions
   and occasionally mild cardiomegaly. May mimic RDS, MAS or
   neonatal pneumonia, but resolves within 2–3 days.
3. Meconium aspiration syndrome (MAS)—predominantly in term
   and postmature babies. Coarse linear and irregular opacities of
   uneven size, generalized hyperinflation and focal areas of collapse.
   Spontaneous pneumothorax in 20%. Pleural effusion in up to 2/3;
   supposedly never seen in RDS. No air bronchograms. High risk of
   superimposed infection.
4. Pneumonia—in <1% of newborns. Risk factor: prolonged rupture
   of membranes. Most commonly group B streptococcus. Segmental
   or lobar consolidation. Pleural effusions may be large, and suggest
   diagnosis. May resemble RDS or MAS, but should be suspected if
   unevenly distributed.
5. Pulmonary haemorrhage—75% are <2.5 kg. Onset at birth or
   delayed several days. May occur after surfactant therapy, probably
   due to left-to-right shunting. Resembles MAS or RDS.
6. Upper airway obstruction—e.g. choanal atresia, micrognathia.
7. Abnormal thoracic cage.
   (a) Neuromuscular disorders—often with thin ribs and clavicles.
   (b) Skeletal dysplasias—e.g. Jeune’s asphyxiating thoracic
   dysplasia, thanatophoric dwarfism, osteogenesis imperfecta
   and metatropic dwarfism.
   (c) Pulmonary hypoplasia—e.g. due to fetal renal failure (Potter
   sequence) or primary (rare).
   (d) Major abdominal wall defects (exomphalos/gastroschisis)—
   short, down-sloping ribs with ‘long’ chest.
8. Infant-onset childhood interstitial lung disease (chILD)—wide
   variety of rare pathologies (see Section 14.37). Variable appearance
   from complete bilateral white-out to normal

Question 68

NEONATAL RESPIRATORY DISTRESS

With mediastinal shift away from the abnormal side 5

Answer 68

1. Diaphragmatic hernia—six times more common on the left side.
   Multiple lucencies due to gas-containing bowel in the chest.
   Herniated bowel may appear solid if X-rayed too early, but there
   will still be a paucity of gas in the abdomen. Liver herniation
   present in large hernias, bad prognostic sign. Displaces umbilical
   venous catheters.
2. Congenital lobar overinflation (CLO)—left upper > right middle
   > right upper lobe, with compression of the lung base (cf.
   pneumothorax which produces generalized compression). CT is
   useful, particularly to exclude extrinsic compression of a bronchus
   by an aberrant vessel or foregut duplication cyst.
3. Large congenital pulmonary airway malformation (CPAM)—
   translucencies of various shapes and sizes scattered throughout an area of opaque lung with well-defined margins. Types 0–IV, varying
   from cystic to apparently solid. Generally asymptomatic unless very
   large or superadded infection.
4. Pneumothorax—may complicate resuscitation or positive pressure
   ventilation, or may be spontaneous. Spontaneous pneumothorax is
   associated with pulmonary hypoplasia, e.g. in Potter sequence. In
   the supine neonate, pleural air collects anteriorly and may not
   collapse the lung medially. In the absence of a lung edge, other
   signs include:
   (a) Sharp ipsilateral heart border.
   (b) Depression or inversion of the ipsilateral hemidiaphragm with
   a deep lateral sulcus.
   (c) Sharp ipsilateral parietal pleura in the upper medial part of the
   hemithorax. If there is tension this may herniate across the
   superior mediastinum.
   (d) Medial deviation of the ipsilateral compressed thymic lobe.
   (e) Mediastinal shift to the contralateral side.
5. Pleural fluid—effusion (especially in congenital heart disease),
   chylothorax (especially in Noonan and Turner syndromes),
   empyema (rare)

Question 69

NEONATAL RESPIRATORY DISTRESS

With mediastinal shift towards the abnormal side 3

Answer 69

1. Atelectasis—most commonly due to incorrect placement of an
   endotracheal tube down a major bronchus. Other causes include
   extrinsic compression (e.g. large duplication cyst, aberrant
   vasculature), intrinsic causes (e.g. tracheobronchomalacia), luminal
   obstruction by a large mucus plug or, rarely, primary atelectasis
   without another abnormality.
2. Pulmonary agenesis/aplasia—rare. May be difficult to
   differentiate from collapse but other congenital defects, especially
   hemivertebrae, are often present. Agenesis = no bronchus; aplasia
   = rudimentary bronchus present.
3. Unilateral pulmonary hypoplasia—most commonly due to
   compression, e.g. by diaphragmatic hernia. May also be associated
   with vascular anomalies, e.g. absent pulmonary artery and
   anomalous venous drainage (scimitar syndrome).

Question 70

NEONATAL RESPIRATORY DISTRESS

Other causes 4

Answer 70

1. Cardiac causes—e.g. congenital heart diseases.
2. Cerebral causes—e.g. haemorrhage, oedema, drugs. After
   cardiopulmonary causes, these account for 50% of the remainder.
3. Metabolic causes—metabolic acidosis, hypoglycaemia and
   hypothermia.
4. Abdominal causes—massive organomegaly, e.g. polycystic
   kidneys, elevating the diaphragms

Question 71

RING SHADOWS IN A CHILD

Neonate 5

Answer 71

1. Diaphragmatic hernia—unilateral.
2. Pulmonary interstitial emphysema (PIE)—secondary to ventilator
   therapy. Linear lucencies, unilateral or bilateral. Usually transient,
   but may persist.
3. CPAM—Stocker types I/IV (at least one cyst >2 cm) and type II (all
   cysts <2 cm). Unilateral focal lucency/lucencies. Type III is
   microcystic and appears solid.
4. Bronchopulmonary dysplasia (BPD)—aka chronic lung disease of
   prematurity. Bilateral, diffuse ‘bubbly lung’ appearances, with
   alternating areas of overinflation and atelectasis.
5. Cystic lung disease in chromosomal disorders—especially
   Down’s.

Question 72

PULMONARY RING SHADOWS IN A CHILD

Older child 6

Answer 72

1. Bronchiectasis—postinfective, cystic fibrosis, primary ciliary
   dyskinesia, immunodeficiency, etc.
2. Pneumatocoeles—e.g. postinfective, ventilation-induced.
3. Respiratory papillomatosis—multiple cystic lesions with nodular
   walls on CT. Laryngeal and tracheal involvement is usually also
   present.
4. Pleuropulmonary blastoma (type 1)—indistinguishable from type
   I/IV CPAM on imaging and similar histologically to type IV CPAM.
5. Langerhans cell histiocytosis*—lung involvement very rare in
   children.
6. Neurofibromatosis*—upper zone cysts/bullae

Question 73

INTERSTITIAL LUNG DISEASE UNIQUE
TO CHILDHOOD
Very rare conditions divided into infant or later onset 2

Answer 73

1. Disorders of infancy.
   (a) Diffuse developmental disorders—e.g. congenital alveolar
   dysplasia, alveolar capillary dysplasia with misalignment of
   pulmonary veins.
   (b) Lung growth abnormalities—e.g. pulmonary hypoplasia,
   chronic BPD, cystic disease in Down’s.
   (c) Conditions of undefined origin—e.g. pulmonary interstitial
   glycogenosis, neuroendocrine hyperplasia of infancy.
   (d) Genetic surfactant dysfunction disorders—most commonly
   surfactant protein B/C or ABCA3 mutations.
2. Disorders not specific to infancy.
   (a) Normal host—e.g. postinfective constrictive obliterative
   bronchiolitis.
   (b) Systemic disease processes—e.g. storage disorders (Gaucher,
   Niemann-Pick).
   (c) Immunocompromise—e.g. lymphocytic interstitial pneumonitis
   in HIV (rare but much more common in children with AIDS
   versus adults with AIDS).
   (d) Masqueraders of interstitial lung disease—e.g. pulmonary
   hypertension, lymphatic disorders.

Question 74

ANTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Congenital 3

Answer 74

1. Normal thymus—see Section 14.38.
2. Lymphangioma—nearly all extend into the mediastinum from the
   neck. Cystic.
3. Morgagni hernia—anterior, usually on the right side.

Question 75

ANTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Neoplastic 5

Answer 75

1. Lymphoma* and leukaemia—most common cause of an anterior
   mediastinal mass in children. The majority are due to Hodgkin
   disease. At presentation, enlarged mediastinal lymph nodes (LN)
   are seen in 85% of Hodgkin, 50% of non-Hodgkin and 5%–10%
   of leukaemias. The lymphadenopathy is usually confluent and
   homogeneous on CT. Comparing mediastinal involvement in
   Hodgkin versus non-Hodgkin lymphoma After lymphoma treatment, a residual anterior mediastinal mass
   may present a diagnostic dilemma. If CT shows this to be
   homogeneous and there is no other lymphadenopathy then a
   tumour is unlikely to be present. PET-CT is currently used to risk
   stratify and determine whether radiotherapy is needed.
2. Germ cell tumours—5%–10% of germ cell tumours arise in the
   mediastinum. Two age peaks: at 2 years and in adolescence. 60%
   are benign teratomas. Endodermal sinus (yolk sac) tumours are
   more aggressive. Seminomas rare. Tumours may contain
   calcification (including teeth), fat and cystic/necrotic areas. Large size, marked mass effect and local infiltration suggest an aggressive
   lesion.
3. Thymic cysts—either congenital, or in young children with LCH,
   or in HIV/EBV-driven lymphoproliferative disease.
4. Thymolipoma—contains fat and thymic tissue.
5. Thymoma—1%–2% of mediastinal tumours in childhood. Most
   occur >10 years of age. Linear calcification in 10%. Only rarely
   associated with myasthenia gravis.

Question 76

ANTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Inflammatory 1

Answer 76

1. Lymphadenopathy—less common than neoplasia. Most frequent
   causes are TB and histoplasmosis. Involved nodes typically show
   central necrosis

Question 77

MIDDLE MEDIASTINAL MASSES

IN CHILDHOOD 20%

Answer 77

Neoplastic
Most middle mediastinal tumours are extensions of those
which arise primarily in the anterior mediastinum (see
Section 14.39).
Inflammatory
1. Lymphadenopathy—TB, histoplasmosis and sarcoidosis (NB:
pulmonary sarcoid is very rare before early teens).

Question 78

MIDDLE MEDIASTINAL MASSES
IN CHILDHOOD
Congenital 4

Answer 78

1. Foregut duplication cysts—account for 10%–20% of paediatric
   mediastinal masses. The spectrum of abnormalities includes:
   (a) Bronchogenic cyst—abnormal lung budding and
   development of ventral foregut during first trimester. Round/
   oval, well-defined, unilocular and homogeneous mass; usually
   0–20 HU, but can be up to 100 HU due to mucus,
   haemorrhage or even milk of calcium contents. There may be
   airway obstruction and secondary infection, both within the
   cyst and in the surrounding lung. May rarely communicate
   with the tracheobronchial tree, resulting in a cavity ± infection.
   Most commonly attached to the carina, but can be located
   anywhere along tracheobronchial tree, e.g. paratracheal, hilar,
   intrapulmonary, paraoesophageal.
   (b) Oesophageal duplication cyst—abnormal development of the
   posterior division of the embryonic foregut. Less common
   than bronchogenic cysts, usually larger and along the upper
   third of the oesophagus, situated to the right of the midline
   extending into the posterior mediastinum. May produce
   symptoms related to oesophageal or tracheobronchial tree
   compression. May contain ectopic gastric mucosa (+ve 99mTc-pertechnetate scan), which causes ulceration,
   haemorrhage or perforation. Communication with the
   oesophageal lumen is rare.
   (c) Neurenteric cyst—failure of separation of gastrointestinal tract
   from primitive neural crest. Located in the middle or posterior
   mediastinum, contains neural tissue and maintains a
   connection with the spinal canal. R>L. Vertebral body
   anomalies (hemivertebra, butterfly vertebra and scoliosis) are
   usually superior to the cyst.
2. Lymphangioma—5% of lymphangiomas in the neck extend into
   the mediastinum. Most are present at birth. Cystic ± solid
   components on imaging.
3. Congenital hiatus hernia—less common than other congenital
   diaphragmatic hernias.
4. Achalasia—rare in children

Question 79

POSTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Neoplastic 2

Answer 79

1. Ganglion cell tumours—neuroblastoma (most malignant, usually
   <5 years), ganglioneuroblastoma (malignant potential, age 5–10 years) and ganglioneuroma (benign, usually >10 years). Imaging
   features of all three types are similar but metastases do not occur
   with ganglioneuroma. Plain films show a paravertebral soft-tissue
   mass with calcification in 30%. Thinning/separation of posterior
   ribs and enlargement of intervertebral foramina may be seen. CT
   shows calcification in 90%. Both CT and MRI may show extradural
   extension.
2. Nerve sheath tumours—benign (schwannoma, neurofibroma) or
   malignant peripheral nerve sheath tumour

Question 80

POSTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Congenital 1

Answer 80

1. Bochdalek hernia—most present at, or shortly after, birth with
   respiratory distress, but 5% present after the neonatal period.
   Rarely it may complicate group B streptococcal infection. A
   herniated liver/kidney may mimic a mass or pleural effusion, and a
   herniated bowel may mimic a pneumothorax, pneumatocoeles or
   CPAM. Bochdalek hernias include:
   (a) Persistence of the pleuroperitoneal canal with a posterior lip of
   diaphragm.
   (b) Larger defects with no diaphragm.
   (c) Herniation through the costolumbar triangles.

Question 81

POSTERIOR MEDIASTINAL MASSES
IN CHILDHOOD
Other 1

Answer 81

1. Extramedullary haematopoiesis—in children, usually related to
   thalassaemia or sickle cell disease. Single or multiple paravertebral
   masses with features of the underlying cause

Question 82

SOLITARY PULMONARY MASS
IN CHILDHOOD
Pseudomass lesions 4

Answer 82

1. Round pneumonia—may contain air-bronchograms. Rarer >8
   years.
2. Encysted pleural effusion—usually an elliptiform mass in right
   midzone. Lateral film confirms.
3. Mucus plug in cystic fibrosis—can be large. CT confirms
   location.
4. Vasculitis

Question 83

SOLITARY PULMONARY MASS
IN CHILDHOOD
Nonneoplastic lesions 6

Answer 83

1. Pulmonary sequestration—focal area of lung that does not
   communicate with the bronchial tree or pulmonary arteries,
   appearing as a nonaerated mass with systemic arterial supply
   (usually from descending aorta). Two types:
   (a) Intralobar—most common type. No separate pleural covering,
   usually has pulmonary venous drainage. Typically in lower
   lobes (L>R). Usually presents in older children or adolescents
   with recurrent infection.
   (b) Extralobar—has its own separate pleural covering, usually has
   systemic venous drainage. Typically in left lower lobe, but can
   be subdiaphragmatic. Usually presents in neonates with
   respiratory distress. Often associated with other congenital
   anomalies.
2. Intrapulmonary bronchogenic cyst—well-defined rounded lesion
   that may contain air–fluid level, particularly if a previous infection.
3. CPAM—type III is microcystic and appears solid. Type I/II are fluidfilled at birth and gradually become air-filled (often reimaged at 3
   months). Note that CPAM-sequestration hybrid lesions can occur
   (looks like CPAM but has systemic arterial supply).
4. Granuloma—most common after TB or histoplasmosis. Usually
   small and calcified.
5. Pulmonary AVM—may visualize draining vein.
6. Bochdalek hernia—due to defect in posterior diaphragm; located
   at lung base, well-defined cranial margin. May contain abdominal
   viscera, e.g. kidney

Question 84

SOLITARY PULMONARY MASS
IN CHILDHOOD
Neoplastic lesions 7

Answer 84

Malignant
1. Solitary metastasis—most commonly Wilms tumour and
sarcomas. Note that ~one-third of lung nodules in children with a
known primary tumour are NOT metastases, e.g. drug reaction,
intrapulmonary lymph node, etc. Lung metastases are rarely an
incidental finding in children.
2. Neuroendocrine tumour—80% are carcinoids. Usually malignant,
frequently endobronchial, causing lobar collapse or overinflation.
Carcinoid syndrome less common in pulmonary carcinoids than
tumours elsewhere.
3. Pleuropulmonary blastoma (PPB)—may be cystic (type I, mimics
CPAM), mixed (type II) or solid (type III). Can be very large, often
peripheral and locally invasive.
4. Bronchogenic carcinoma—most commonly mucoepidermoid
carcinoma.
Benign
1. Inflammatory myofibroblastic tumour—neoplastic subset of
inflammatory pseudotumours. Most common primary lung
neoplasm in children. Usually benign but can be malignant.
Variable size, usually peripheral. Calcified in 25%.
2. Hamartoma—occasionally calcified. Slow-growing, well-defined.
3. Chondroma—e.g. in Carney triad.

Question 85

MULTIPLE PULMONARY NODULES IN
A CHILD
Benign 6

Answer 85

1. Miliary TB*/other granulomatous infection—miliary pattern of
   haematogenous spread should be distinguished from ‘tree-in-bud’
   pattern of endobronchially disseminated TB.
2. Septic emboli—frequently cavitary.
3. Wegener’s granulomatosis*—may cavitate.
4. Respiratory papillomatosis—represents pulmonary seeding of
   laryngeal papillomas, occurring in 1% of cases. Nodular and
   cystic lesions. Poor prognosis. Risk of malignant transformation.
5. Prior varicella infection—can result in multiple small calcified
   granulomas.
6. Multiple AVMs—2/3 associated with HHT. Multiple in most cases,
   usually lower lobes

Question 86

MULTIPLE PULMONARY NODULES IN
A CHILD
Malignant 2

Answer 86

1. Multiple pulmonary metastases—Wilms tumour and sarcomas
   (calcified nodules in osteosarcoma) are the most common primary
   sites. Multiple nodules are more likely to be malignant than a
   single nodule.
2. Lymphoma* or PTLD.

Question 87

SITUS AND CARDIAC MALPOSITIONS

Visceral situs 4

Answer 87

1. Situs solitus—normal position, i.e. liver on the right, gastric
   bubble on the left and normal airway anatomy.
2. Situs inversus—completely switched positions, i.e. liver on the left,
   stomach bubble on the right, inverted airway anatomy (i.e. earlier
   take-off of the left-sided upper lobe bronchus).
3. Left atrial isomerism (LAI)—bilateral left-sidedness, i.e. long main
   bronchi passing inferior to the pulmonary arteries with late
   upper-lobe take-off (as per a normal left bronchus), bilateral
   bilobed lungs, azygous continuation of the IVC (absent
   intrahepatic IVC with resultant large azygous venous system)
   and polysplenia. Associated with complex congenital heart
   disease.
4. Right atrial isomerism (RAI)—bilateral right-sidedness, i.e.
   bilateral short main bronchi with early upper-lobe take-off (as per a
   normal right bronchus), bilateral trilobed lungs, ± asplenia.
   Associated with more severe cardiac and extracardiac
   malformations than left atrial isomerism

Question 88

CONGENITAL HEART DISEASES

Plethoric Acyanotic 4

Answer 88

1. VSD
2. ASD
3. AVSD
4. APW

Question 89

CONGENITAL HEART DISEASES

Plethoric Cyanotic 6

Answer 89

1. d-TGA (vessels are switched, cf l TGA - ventricles switched)
2. TAPVD
3. Truncus arteriosus ( common trunk + VSD, 4 types)
4. HLHS ( hypoplastic left heart xd, small asc aorta)
5. Tricuspid atresia + TGA
6. Single ventricle

Question 90

CONGENITAL HEART DISEASES

Oligaemic Cyanotic 4

Answer 90

1. Tetralogy of Fallot
2. Ebstein’s anomaly
3. Tricuspid atresia
4. Pulmonary atresia

Question 91

CONGENITAL HEART DISEASES

Normal lung fields Acyanotic 3

Answer 91

1. Aortic stenosis
2. Coarctation of aorta
3. Pulmonary stenosis

Question 92

ABDOMINAL MASS IN A CHILD

Renal (55%) 3

Answer 92

1. Renal tumours
2. Hydronephrosis
3. Cysts

Question 93

ABDOMINAL MASS IN A CHILD

Non-renal retroperitoneal (23%) 9

Answer 93

1. Neuroblastoma (21%)—most common solid extracranial
   childhood malignancy. 90% <5 years, median age 2 years.
   Accounts for 50% of all neonatal tumours. 70% are metastatic at
   presentation.
   (a) Site—adrenal (40%), abdominal sympathetic chain (25%),
   posterior mediastinal sympathetic chain (15%), neck (5%),
   pelvis (5%) and unknown (10%).
   (b) Clinical presentation.
   (i) Local effects—pain, mass, spinal cord compression,
   dyspnoea, dysphagia.
   (ii) Effects of metastases—blueberry muffin syndrome (skin
   metastases), scalp masses, limping, bone pain, weight
   loss, anaemia, fatigue, etc.
   (iii) Effects of hormone secretion—severe diarrhoea (due to
   vasoactive intestinal peptides), hypertension, flushing and
   sweating.
   (iv) Opsomyoclonus—jerky eye movements, myoclonic jerks
   and cerebellar ataxia; 50% will have neuroblastoma,
   therefore must investigate thoroughly.
   (c) Plain films—calcification (in 2/3), loss of psoas outline, bony
   metastases, enlarged intervertebral foramina, and in the chest,
   abnormal posterior ends of ribs.
   (d) US—heterogeneous echogenic mass + vascularity ±
   calcification.
   (e) CT—heterogeneous soft-tissue mass with calcification in nearly
   all. Encasement rather than displacement of major vessels.
   Paravertebral fat plane is often obliterated ± intraspinal
   extension via the intervertebral foramina.
   (f) MRI—heterogeneously T1 hypointense and T2 hyperintense.
   Calcification is not as readily recognized as on CT, but MRI is
   superior for lymph-node metastases, liver metastases and
   extradural spread of tumour.
   (g) Nuclear imaging—bone scan (for cortical disease) and MIBG
   scan (for medullary disease) are complementary techniques to
   identify skeletal metastases.
2. Lymphoma*—uncommon in the absence of mediastinal disease.
   NHL > Hodgkin disease in children <5 years.
3. Germ cell tumours—usually represent a metastasis from a gonadal
   primary. The most common primary retroperitoneal GCT in
   children is benign teratoma; typically it contains variable amounts
   of fluid, soft tissue, fat and calcification.
4. Other ganglion cell tumours—i.e. ganglioneuroma (benign,
   usually >10 years) and ganglioneuroblastoma (malignant
   potential, age 5–10 years). Similar imaging features to
   neuroblastoma, but ganglioneuroma does not metastasize,
   is less commonly calcified and may have a characteristic whorled
   appearance on MRI.
5. Other adrenal masses—see Section 14.56.
6. Other neurogenic tumours—schwannoma, neurofibroma
   (multiple in NF1, may mimic lymphadenopathy), paraganglioma
   (hypervascular).
7. Sarcomas—most commonly rhabdomyosarcoma. Heterogeneous,
   often with areas of necrosis, but calcification is rare (in contrast to
   neuroblastoma)
8. Lipoblastoma—contains fat. NB: lipomas and liposarcomas are
   very rare in children.
9. Intraabdominal pulmonary sequestration—pyramidal suprarenal
   solid-cystic mass, separate from adrenal. Has its own arterial
   supply, usually from aorta

Question 94

ABDOMINAL MASS IN A CHILD

Gastrointestinal (18%) 7

Answer 94

1. Appendix mass/abscess (10%)—particularly spreads to pouch
   anterior to rectum.
2. Hepatoblastoma—see Section 14.53.
3. Haemangioma—commonly multiple, involving entire liver; may
   also involve mesentery. Large haemangiomas may bleed and
   appear heterogeneous, but shrink with time. Rarely calcify. May be
   associated with congestive heart failure and cutaneous
   haemangiomas.
4. Choledochal cyst—the classic triad of mass, pain and jaundice is
   only present in 10%. Dynamic radionuclide scintigraphy (HIDA
   scan) is diagnostic. See Section 14.55.
5. Enteric duplication cyst.
6. Mesenteric cyst.
7. Meconium pseudocyst—complication of meconium peritonitis
   in newborns, forming a rim-calcified pseudocyst in the
   peritoneal cavity. Other peritoneal calcifications may also
   be present.

Question 95

ABDOMINAL MASS IN A CHILD

Genital (4%) 3

Answer 95

1. Ovarian cysts or teratoma.
2. Urogenital sinus-associated cyst.
3. Fetus in fetu—malformed parasitic fetus located inside the body
   of its viable twin.

Question 96

ABDOMINAL CYST IN A FETUS

OR NEONATE 11

Answer 96

1. Ovarian—most common cyst in a female infant; occasionally
   cystic teratoma.
2. Bowel—enteric duplication cyst, mesenteric/omental cysts and
   atresias.
3. Renal—hydronephrosis (± urinoma), multicystic dysplastic kidney
   and autosomal recessive polycystic kidney disease (markedly
   enlarged kidneys + microcysts).
4. Liver/biliary tree—choledochal cyst, hydatid cyst, mesenchymal
   hamartoma (cystic) and umbilical vein varix.
5. Peritoneum—meconium pseudocyst.
6. Bladder—urachal cyst and megacystis.
7. Genital tract—urogenital sinus.
8. Spleen—simple cyst and hydatid.
9. Adrenal—endothelial/epithelial cysts, hydatid and following
   haemorrhage.
10. Spine—anterior meningocoele and sacrococcygeal teratoma.
11. Pulmonary sequestration—intraabdominal suprarenal location

Question 97

INTESTINAL OBSTRUCTION IN
A NEONATE
High intestinal obstruction - to jejunum
6

Answer 97

1. Duodenal atresia/stenosis/web—marked dilatation of the
   proximal duodenum with the ‘double bubble’ sign, which may
   also be seen on US of the fetus (50% have a history of
   polyhydramnios). No gas distally when there is atresia, but a variable amount of gas in the distal bowel when there is stenosis.
   Duodenal web may produce a ‘windsock’ appearance as web
   balloons into distal duodenum. Bile-stained vomiting in the
   majority. Associated with annular pancreas, Down’s syndrome,
   cardiac anomalies, oesophageal atresia and other anomalies of GI
   tract. A preduodenal portal vein may be seen—this is associated
   with intrinsic duodenal obstruction (the vein is not the direct cause
   of obstruction).
2. Malrotation and volvulus—sudden onset of bile-stained vomiting.
   Few radiological signs if the obstruction is recent, intermittent or
   incomplete. Due to its acute nature, the duodenum is not dilated.
   If not recognized, progresses to bowel ischaemia, infarction and
   death. A contrast study should show the normal C-shaped
   duodenal loop terminating to the left of the left-sided pedicle at
   the same level as the duodenal cap. In malrotation without
   volvulus the duodenojejunal flexure is abnormal, to the right of
   and below its normal position. Volvulus with incomplete
   obstruction leads to a ‘corkscrew’ jejunum. With complete
   obstruction, the distal duodenum terminates as a beak.
3. Malrotation with obstructing Ladd’s bands—these fibrous bands
   connect the malrotated caecum to the right posterolateral
   abdominal wall and typically cross the duodenum (D2). They can
   cause obstruction even in the absence of volvulus.
4. Jejunal atresia—constitutes 50% of small bowel atresias, and 50%
   are associated with other atretic sites distally (ileum > colon). AXR
   demonstrates three (‘triple bubble’) or more dilated, air-filled
   loops. Colon is usually normal in calibre.
5. Pyloric atresia—rare.
6. Pyloric or prepyloric membrane/antral web—gastric outlet
   obstruction with a normal pylorus and the appearance of two
   duodenal caps. The web may be identified by US

Question 98

INTESTINAL OBSTRUCTION IN A NEONATE

Low intestinal obstruction 9

Answer 98

1. Meconium ileus—mottled lucencies (‘soap bubble’ appearance)
   due to gas trapped in meconium but only few fluid levels (since it
   is very viscous). Bowel loops of variable calibre. Rapid appearance
   of fluid levels suggests volvulus. Peritoneal calcification (due to
   perforation in utero) is seen in 30%. Secondary microcolon on
   contrast enema, which also shows meconium pellets in the distal
   ileum. Cystic fibrosis in the majority.
2. Hirschsprung’s disease—multiple dilated loops of bowel.
   Diagnosis is made by contrast enema, which shows normal or
   small size of aganglionic distal bowel with a transition zone at the
   junction with proximal dilated ganglionic bowel; classically
   reversed rectosigmoid ratio. The rectum may have a serrated
   corkscrew appearance. Total colonic aganglionosis may lack a
   transition zone and present as diffuse microcolon
3. Ileal atresia—50% of small bowel atresia, may be multiple ±
   jejunal atresia. Multiple dilated loops with fluid levels. Secondary
   microcolon.
4. Incarcerated inguinal hernia.
5. Small left colon syndrome (SLCS)—due to functional colonic
   immaturity; 50% associated with maternal diabetes. Small colon
   on enema up to level of splenic flexure, ± meconium plugs. Infants
   should be followed up to exclude Hirschsprung’s.
6. Meconium plug syndrome—meconium plugs in distal colon.
   Overlaps with SLCS. May be a presenting feature of Hirschsprung’s
   or cystic fibrosis (but note this is not the same as meconium ileus).
7. Inspissated milk—presents from 3 days to 6 weeks of age. Dense,
   amorphous intraluminal masses frequently surrounded by a rim of
   air, ± mottled lucencies internally. Usually resolves spontaneously.
8. Colonic atresia—5%–15% of intestinal atresias. AXR may be
   similar to other distal bowel obstructions but some infants show a
   huge, disproportionately dilated loop (between the atretic segment
   and a competent ileocaecal valve).
9. Anorectal malformation/imperforate anus.
   (a) High—± sacral agenesis/hypoplasia and gas in the bladder
   (due to a rectovesical or rectourethral fistula). Currarino triad =
   anorectal malformation, sacral dysgenesis and sacrococcygeal
   teratoma variant/meningocoele.
   (b) Low—± perineal or urethral fistula

Question 99

INTRAABDOMINAL CALCIFICATIONS IN
THE NEWBORN
5

Answer 99

1. Meconium peritonitis—antenatal bowel perforation results in aseptic peritonitis, which rapidly calcifies. Calcification occurs in the peritoneum itself most commonly, but also in the bowel wall and in the scrotum and may be punctate, linear or plaque-like. The most common causes are meconium ileus and ileal atresia, but any cause of bowel obstruction may be associated.
2. Meconium pseudocyst—cyst-like mass with peripheral calcification
   resulting from walling-off of extruded meconium after perforation
3. Bowel calcification—intramural lymphatic or intraluminal meconium calcification in cases of distal bowel obstruction, particularly meconium ileus, total colonic aganglionosis and anorectal malformations. Occasionally a duodenal duplication cyst may calcify and appear as a spherical upper abdominal calcification.
4. Hepatic calcification.

5. Adrenal calcification—following adrenal haemorrhage; rarely in 
Wolman disease (deficiency of acid lipase/acid esterase,accumulation of lipid esters in multiple tissues including the liver, spleen, lymph nodes, and small bowel)

Question 100

ABNORMALITIES OF BOWEL ROTATION 7

Answer 100

1. Exomphalos—total failure of the bowel to return to the abdomen
   from the umbilical cord. Bowel is contained within a sac.
2. Gastroschisis—bowel protrudes through a defect in the abdominal
   wall without a sac, classically in a right paraumbilical position.
3. Nonrotation—usually an asymptomatic condition with the small
   bowel on the right side of the abdomen and the colon on the left
   side. Small and large bowel lie on either side of the SMA with a
   common mesentery. Imaging shows the SMV lying to the left of
   the SMA (opposite of normal arrangement).
4. Malrotation—the duodenojejunal flexure lies to the right and
   caudad to its usual position. The caecum is usually more cephalad
   than normal, but is normally sited in 5%. Malrotation is a frequent
   feature of diaphragmatic hernia, abdominal wall defects and
   visceral heterotaxy. CT/US shows the SMV to the left of the SMA.
   A normal US does not, however, exclude malrotation (3%
   false-negative rate); upper GI contrast study remains the gold
   standard. At risk of life-threatening volvulus.
5. Reverse rotation—rare. Colon lies dorsal to the SMA with jejunum
   and duodenum anterior to it.
6. Paraduodenal hernia—rare.
7. Cloacal exstrophy—rare. No rotation of the bowel, and the ileum
   and colon open separately onto the extroverted area in the midline
   below the umbilical cord. Associated with ‘open-book pelvis’ and
   split genitalia

Question 101

GAS IN THE PORTAL VEINS ( PAED)

5

Answer 101

1. Necrotizing enterocolitis—seen in 10%. Necrotic bowel wall
   allows gas or gas-forming organisms into the portal circulation.
2. Umbilical vein catheterization—with inadvertent injection of air.
3. Postoperative—e.g. after liver transplant or corrective bowel
   surgery.
4. Haemolytic disease of the newborn.
5. Neonatal viral gastroenteritis

Question 102

HEPATIC MASSES IN CHILDREN
Malignant tumours (two-thirds) 5

Answer 102

1. Metastases—from neuroblastoma or Wilms tumour.
2. Hepatoblastoma—M>F, usually <5 years old (peak 18-24 months).
   Serum αFP usually raised. Typically a large well-defined
   heterogeneous mass ± vascular invasion ± areas of necrosis,
   haemorrhage and calcification. Metastasizes to lungs, abdominal
   nodes and bones. Associated with Beckwith-Wiedemann syndrome,
   hemihypertrophy and FAP.
3. Hepatocellular carcinoma—similar features to hepatoblastoma,
   but occurs in an older age group (>5 years, peak 12-14 years with
   a smaller peak at 2-4 years), is more likely to be multifocal, and has
   a worse prognosis. Associated with chronic liver disease (cirrhosis,
   glycogen storage disease 1, tyrosinaemia, biliary atresia, chronic
   hepatitis, alpha-1 antitrypsin deficiency).
4. Undifferentiated embryonal sarcoma of the liver—rare; majority
   are 6–10 years of age.
5. Teratoma.

Question 103

HEPATIC MASSES IN CHILDREN
Benign tumours (one-third) 3

Answer 103

1. Infantile hepatic haemangioma—most common benign tumour.
   Often presents in the newborn period with hepatomegaly and
   congestive cardiac failure ± skin haemangiomas (50%) ±
   consumptive coagulopathy (thrombocytopenia). Unifocal or
   multifocal, well-defined or diffuse. Typical enhancement pattern on
   CT with early peripheral enhancement + variable delayed
   centripetal filling over 30 minutes. On MRI the lesions have a
   nonspecific T1 hypointense and T2 hyperintense appearance with
   variable areas of hypointensity corresponding to fibrosis and
   haemosiderin deposition. 99mTc-labelled red cells will accumulate in this tumour. In the neonate, this and cavernous haemangioma
   may be considered together.
2. Mesenchymal hamartoma—second most common benign
   tumour. <2 years of age. May be (multi)cystic or stromal, with a
   ‘Swiss cheese’ appearance. Solid components may enhance.
3. Adenoma—uncommon in paediatric population. Solitary or
   multiple, occurring spontaneously or complicating glycogen
   storage disease, Fanconi anaemia treated with anabolic steroids,
   and teenagers on the oral contraceptive pill

Question 104

HEPATIC MASSES IN CHILDREN

Other lesions 3

Answer 104

1. Cysts—simple, choledochal or hydatid.
2. Focal nodular hyperplasia—2%–6% of hepatic lesions in
   childhood. See Chapter 8.
3. Abscess

Question 105

FETAL OR NEONATAL LIVER
CALCIFICATION
Peritoneal surface of liver 2

Answer 105

1. Meconium peritonitis—solid or cystic masses with calcified walls.
2. Plastic peritonitis due to ruptured hydrometrocolpos—similar
   appearance to meconium peritonitis but US may show a dilated,
   fluid-filled uterus and vagina.

Question 106

FETAL OR NEONATAL LIVER
CALCIFICATION
Parenchymal 3

Answer 106

1. Congenital infections—TORCH complex (toxoplasmosis, rubella,
   CMV, herpes simplex) and varicella. Randomly scattered nodular
   calcification. Often calcification elsewhere and other congenital
   abnormalities.
2. Tumours—haemangioma, hamartoma, hepatoblastoma, teratoma
   and metastatic neuroblastoma. Complex mass on US.
3. Haematoma—following vascular catheter injury, or haemorrhage
   in a vascular mass such as haemangioma

Question 107

FETAL OR NEONATAL LIVER
CALCIFICATION
Vascular

Answer 107

1. Portal vein thromboemboli—subcapsular branching calcification.
2. Ischaemic infarcts—branching calcifications but distributed
   throughout the liver

Question 108

JAUNDICE IN INFANCY

Answer 108

1. Neonatal cholestasis—due to breastfeeding, maternal diabetes,
   drugs and total parenteral nutrition. Usually transient.
2. Haemolytic anaemias—hereditary, ABO or Rhesus
   incompatibilities. Unconjugated hyperbilirubinaemia (unlike the
   other causes on this list).
3. Biliary atresia—type 1 involves CBD only; type 2a involves
   CHD only; type 2b involves CHD, CBD and cystic duct; type 3
   involves all extrahepatic ducts including left and right hepatic
   ducts (>90% of cases). May be associated with congenital
   anomalies, e.g. polysplenia, intestinal malrotation, azygos
   continuation of IVC, situs inversus and preduodenal portal vein.
   On US, the ‘triangular cord’ sign (band of echogenic fibrous
   tissue at the porta hepatis replacing the bile duct) is highly
   specific. An absent or small irregular gallbladder (gallbladder
   ‘ghost’) is seen in types 2b and 3. A prominent hepatic artery
   may also support the diagnosis, but cannot be used in isolation.
   A normal-sized gallbladder that contracts after a fatty meal
   excludes the diagnosis. On HIDA scan, normal uptake by
   hepatocytes but no excretion into the bowel suggests the
   diagnosis (though alpha-1 antitrypsin may look similar). Operative
   cholangiography is definitive.
4. Neonatal hepatitis—often idiopathic but some cases are viral
   (e.g. hepatitis A–C, rubella, CMV). Liver may be enlarged or
   hyperechoic on US, and the gallbladder may be small due to
   poor hepatocyte function. HIDA scan may show delayed
   hepatocyte uptake, but excretion into bowel is usually normal.
5. Choledochal cyst—may present in the neonatal period or at a
   later age. See Chapter 8. On US: anechoic structure separate from
   the gallbladder, which communicates with the biliary tree. On
   HIDA scan: photopenic area, which accumulates tracer on delayed
   images. Complications include calculi, infection, pancreatitis, biliary
   cirrhosis, portal hypertension and malignancy.
6. Alagille syndrome—hypoplasia of intrahepatic bile ducts,
   cardiovascular abnormalities (especially pulmonary stenosis),
   dysmorphic facies, eye abnormalities, butterfly vertebrae,
   radioulnar synostosis.
7. Metabolic defects—e.g. alpha-1 antitrypsin deficiency,
   galactosaemia, tyrosinaemia and glucose-6-phosphate
   dehydrogenase enzyme deficiency

Question 109

ADRENAL MASS IN CHILDHOOD

Neoplastic 4

Answer 109

Medullary
1. Neuroblastoma, ganglioneuroblastoma, ganglioneuroma—see
Section 14.47.
2. Phaeochromocytoma—uncommon. Mean age 11 years, 25%
bilateral. Associated with MEN type 2, NF1 and vHL.
Cortical
1. Adrenocortical neoplasms—differentiating benign (adenoma)
from malignant (carcinoma) lesions not possible in childhood.
Usually hormonally active and most patients <5 years of age.
2. Malignant rhabdoid tumour—rare, highly aggressive

Question 110

ADRENAL MASS IN CHILDHOOD

Nonneoplastic—rare beyond infancy 5

Answer 110

1. Hyperplasia—e.g. congenital adrenal hyperplasia (characteristic
   cerebriform appearance). Typically bilateral.
2. Haemorrhage—blunt trauma, bleeding diathesis and
   meningococcal sepsis. Avascular on US.
3. Cyst—rare, usually a lymphatic malformation or haemorrhagic
   pseudocyst.
4. Abscess—rare; haematogenous or direct intraperitoneal spread.
5. Calcification—Wolman disease; bilateral enlarged calcified
   adrenals

Question 111

ADRENAL MASS IN CHILDHOOD

Conditions that can mimic adrenal lesions 3

Answer 111

1. Subdiaphragmatic extralobar pulmonary sequestration.
2. Extramedullary hematopoiesis.
3. Diaphragmatic lesions

Question 112

PRIMARY RENAL NEOPLASMS

IN CHILDHOOD 9

Answer 112

1. Wilms tumour—accounts for 87% of pediatric renal masses. Peak
   incidence at 3–4 years of age, 80% present <5 years. Bilateral in
   5%. Associated abnormalities: cryptorchidism, hypospadias,
   hemihypertrophy, sporadic aniridia. Associated syndromes: Denys-Drash (Wilms tumour, male pseudohermaphroditism, progressive glomerulonephritis), WAGR ( Wilms, aniridia, GU malformations, and mental retardation) , Beckwith-Wiedemann (10% will develop
   Wilms tumour). Metastasizes to lungs and liver. 5% have a tumour
   thrombus in the IVC or right atrium. Hypertension in 25%
   (renin-induced). Screening in patients with associated syndromes
   should begin at 6 months of age, mainly by serial US every 3
   months up to 7 years of age.
   (a) Plain film—bulging flank, loss or enlargement of renal outline,
   displacement of bowel gas, loss of psoas outline, calcification
   (10%).
   (b) US—large, well-defined mass, similar or greater echogenicity
   than liver. Solid with haemorrhage/necrosis. Lack of IVC
   narrowing on inspiration suggests occlusion.
   (c) CT—large, well-defined, heterogeneous with foci of low
   attenuation necrosis. Minimal enhancement compared with
   the residual rind of functioning renal tissue. Claw sign (rim
   of preserved renal tissue clawing at the tumour mass).
   (d) MRI—heterogeneous, low T1 signal, high T2 signal.
   Inhomogeneous enhancement compared with residual
   renal tissue.
2. Nephroblastomatosis—nephrogenic rests which maintain the
   potential for malignant induction to Wilms tumour. Seen in up to
   40% of unilateral and 99% of bilateral Wilms tumours. May be
   perilobar (most common, at the lobar surface), intralobar
   (anywhere in the cortex or medulla) or combined. Hypoechoic on
   US, similar signal to renal cortex on MRI. Nonenhancing on CT/
   MRI, therefore best seen on postcontrast images.
3. Congenital mesoblastic nephroma—most common solid renal
   tumour in the newborn. May contain cystic, haemorrhagic or
   necrotic areas. Mean age at diagnosis is 3.5 months. Often
   indistinguishable from Wilms tumour on imaging, but different
   age group.
4. Multilocular cystic nephroma—presents at 3 months to 4 years.
   Multiple cysts of varying size, thin septa only. May contain variable
   signal on MRI due to haemorrhage or protein content. Thick septa,
   nodules or a large solid component suggest Wilms tumour with
   cystic degeneration. Resection is curative, local recurrence is rare.
   Differential diagnosis is a multicystic dysplastic kidney, but this
   typically affects the entire kidney.
5. Angiomyolipoma (AML)—in children, nearly always associated
   with tuberous sclerosis, and typically multiple and bilateral.
   Lesions >3 cm carry increased risk of bleeding. Surveillance with
   US or MRI is recommended 1–2 times yearly if lesions are <3 cm
   and annually if they are bigger. Characteristically contain fat on
   imaging (NB: fat may also occasionally be identified within
   Wilms tumour).
6. Clear cell sarcoma—presents at 3–5 years. Poor prognosis with
   early metastases to bone (usually lytic but may be sclerotic). Never bilateral. Imaging features often similar to Wilms (but different
   pattern of metastases).
7. Rhabdoid tumour of kidney—presents at 3 months to 4.5 years
   (50% in first year). Most malignant renal tumour with poorest
   prognosis. Extrarenal extension or haematogenous metastases (to
   brain or bone) often present at diagnosis. Associated with midline
   posterior cranial fossa tumours. Similar on imaging to Wilms
   tumour; however, areas of necrosis or calcification outlining
   tumour lobules may suggest rhabdoid tumour.
8. Renal cell carcinoma—rare. Differentiating features from Wilms
   tumour are: older age (mean 11–12 years), calcification is more
   common (25%), more homogeneous, smaller at the time of
   diagnosis and haematuria is more common. Poorer prognosis
   compared with Wilms tumour. Similar imaging findings. Associated
   with von Hippel-Lindau disease and tuberous sclerosis.
9. Ossifying renal tumour of infancy (ORTI)—rare benign tumour
   of infancy, which mimics a staghorn calculus. Presents with gross
   hematuria and a calcified mass in the pelvicalyceal system

Question 113

RENAL MASS IN THE NEWBORN AND

YOUNG INFANT 6

Answer 113

1. Hydronephrosis—unilateral or bilateral. The most common cause
   of an abdominal mass in the first 6 months of life.
2. Multicystic dysplastic kidney—unilateral, but 30% have an
   abnormal contralateral kidney (mostly reflux or PUJ obstruction).
   On imaging, presents as multiple cysts replacing the renal
   parenchyma with intervening fibrous tissue.
3. Polycystic kidneys (autosomal recessive)—bilateral. Large and
   highly echogenic on US.
4. Renal vein thrombosis—unilateral or bilateral.
5. Renal neoplasms—e.g. congenital mesoblastic nephroma,
   multilocular cystic nephroma, rhabdoid tumour and ORTI (see
   Section 14.57).
6. Nephroblastomatosis

Question 114

HYDRONEPHROSIS IN A CHILD 5

Answer 114

1. PUJ obstruction—L>R, 20% bilateral. Due to stricture,
   neuromuscular incoordination or aberrant vessels. Contralateral
   kidney may be dysplastic or absent.
2. Primary vesicoureteric reflux without obstruction—usually
   idiopathic. Common in the lower moiety of a duplex system.
3. Vesicoureteric junction (VUJ) obstruction—may be secondary
   to bladder hypertrophy/neurogenic dysfunction or obstructive
   ureterocoele (e.g. upper moiety of a duplex kidney). Primary
   type is more common in males and on the left side. May be
   bilateral.
4. Primary megaureter—represents ureteral atony. Sometimes
   associated with UTI; may be nonobstructive and nonrefluxing.
5. Bladder outflow obstruction—usually due to posterior urethral
   valves (in males), causing bilateral upper tract dilatation.

Question 115

BLADDER OUTFLOW OBSTRUCTION IN

A CHILD 11

Answer 115

1. Vesical diverticulum—posteriorly behind the bladder base. It fills
   during micturition and compresses the bladder neck and
   proximal urethra. M>F.
2. Bladder neck obstruction—e.g. by an ectopic ureterocoele or
   rhabdomyosarcoma.
3. Ectopic ureterocoele—80% are associated with the ectopic
   upper moiety ureter of a duplex kidney. 15% are bilateral. F>M.
   Ectopic ureter may open into the urethra, bladder neck or
   vestibule. Ureterocoele may be largely outside the bladder,
   elevating the bladder base, or may prolapse into the urethra 4. Posterior urethral valves—on MCUG, posterior urethra is dilated
   and the distal urethra is small. Almost exclusively males.
4. Urethral stricture—posttraumatic strictures (e.g. instrumentation
   or catheterization) are most commonly at the penoscrotal
   junction.
5. Cowper’s syringocoele—dilatation of the main duct of the
   bulbourethral (Cowper’s) glands; males only. Filling of Cowper’s
   ducts may be a normal finding. When dilated, occasionally
   presents with haematuria, infection or urethral obstruction.
6. Anterior urethral diverticulum/valve—a saccular wide-necked,
   ventral expansion of the anterior urethra, usually at the
   penoscrotal junction. The proximal lip of the diverticulum may
   show as an arcuate filling defect and during micturition the
   diverticulum expands with urine and obstructs the urethra.
7. Prune-belly and megacystis-microcolon syndromes.
8. Calculus or foreign body.
9. Meatal stenosis—males only; usually a clinical diagnosis, but
   may be detected on MCUG; voiding images should include the
   meatus (external urethral opening).
10. Phimosis—clinical diagnosis

Question 116

VESICOURETERIC REFLUX

Congenital = primary reflux 2

Answer 116

1. Simple congenital reflux—due to VUJ incompetence secondary to
   abnormal tunnelling of distal ureter through bladder. 10% of
   normal Caucasian babies and 30% of children with a first episode
   of UTI. Usually disappears in 80%. Medium- to high-grade reflux
   can lead to renal damage in association with UTI.
2. Reflux associated with duplex kidneys—usually occurs into
   lower-moiety ureter, which has a normal position but abnormal
   tunnelling. Reflux may also occur into a ureterocoele if this everts
   during filling or voiding

Question 117

VESICOURETERIC REFLUX

Acquired = secondary reflux 5

Answer 117

1. Hutch diverticulum—congenital bladder diverticulum at the VUJ.
2. Cystitis—in 50%.
3. Neurogenic bladder.
4. Urethral obstruction—most commonly posterior urethral valves
5. Prune-belly syndrome—almost exclusively males. High mortality.
   Bilateral hydronephrosis and hydroureters with a distended
   bladder. Associated with undescended testes, hypoplasia of the
   anterior abdominal wall and urethral obstruction.

Question 118

RETINOBLASTOMA AND

ITS DIFFERENTIALS

Answer 118

Rare but most common intraocular tumour of childhood; usually presents <5 years. An aggressive malignant tumour, accounts for ~10% of all cancers in the first year of life. Bilateral or multifocal tumours occur in patients with heritable retinoblastoma (~30–60% of cases). If bilateral heritable retinoblastomas occur with a
primary intracranial neuroblastic tumour (usually pineal or parasellar), the syndrome is called ‘trilateral retinoblastoma’.
Leukocoria and strabismus are the most common presenting symptoms.

Differential diagnosis of retinoblastoma
Greater than 50% of children presenting with a clinical diagnosis
of retinoblastoma have another diagnosis, commonly persistent
hyperplastic primary vitreous (PHPV), Coat’s disease or
toxocariasis. Calcification (95% on CT) is the most important
feature that differentiates retinoblastoma from other tumour-like
lesions. None of the conditions in the following table show
calcification <3 years, but above that age some may do so, e.g.
retinal astrocytoma, retinopathy of prematurity and toxocariasis.

Question 119

Coat’s disease

Answer 119

A vascular anomaly of telangiectatic vessels, which leak proteinaceous material into the subretinal space. Usually boys; unilateral. Present at birth but usually asymptomatic until the retina detaches and vision deteriorates.

Question 120

PREVERTEBRAL SOFT-TISSUE MASS ON

THE LATERAL CERVICAL X-RAY 3

Answer 120

1. Trauma/haematoma—± associated fracture.
2. Abscess—± gas lucencies within it. Unlike the normal variant
   described above, these lucencies are constant and persist during
   deep inspiration. A sharp foreign body may be visible within the
   collection.
3. Neoplasms—e.g. lymphangioma, lymphoma, nasopharyngeal
   rhabdomyosarcoma, neuroblastoma and LCH (with vertebra
   plana)

Question 121

NECK MASSES IN INFANTS
AND CHILDREN
Congenital 3

Answer 121

1. Lymphovascular malformations—soft. Lymphangiomas are
   uni- or multilocular and often involve multiple neck spaces.
   Infantile haemangiomas are solid and hypervascular, and typically
   resolve spontaneously.
2. Cysts—firm.
   (a) Thyroglossal—midline position.
   (b) Branchial cleft—lateral position. Second branchial arch
   remnant most common, lying posterior to the submandibular
   gland, lateral to the carotid space and anteromedial to the
   sternomastoid muscle.
   (c) Lingual—including ranula.
   (d) Thymic—rare, remnant of thymopharyngeal duct. Located
   close to carotid sheath, often extends into mediastinum.
   (e) Dermoid/epidermoid/teratoma—midline, often contains fat
   and calcification (except epidermoid, which only contains
   fluid).
3. Ectopic cervical thymic lobe

Question 122

NECK MASSES IN INFANTS
AND CHILDREN
Acquired 7

Answer 122

1. Infective/reactive lymphadenopathy—e.g. viral, bacterial,
   mycobacterial and cat-scratch disease. Nonviral nodal infections
   can lead to suppuration/abscess formation.
2. Malignant neoplasms—e.g. lymphoma, neuroblastoma
   (secondary > primary), rhabdomyosarcoma, LCH (disseminated
   disease in infants) and thyroid cancer (rare, usually papillary).
3. Benign neoplasms—e.g. lipoma, neurofibroma (in NF1),
   pilomatricoma (arises from skin, often calcified), thyroid cyst or
   nodule.
4. Fibromatosis colli—unilateral enlargement of sternocleidomastoid
   muscle in young infants ± torticollis. Thought to be related to birth
   trauma.
5. Trauma/haematoma.
6. Diffuse thyroid enlargement—e.g. Graves’ disease, multinodular
   goitre and Hashimoto’s thyroiditis.
7. Parotitis—e.g. bacterial (unilateral), HIV (bilateral) and Sjögren’s
   (bilateral)

Question 123

CAUSES OF STROKE IN CHILDREN AND

YOUNG ADULTS 7

Answer 123

1. Emboli—cyanotic heart disease (due to R→L intracardiac shunt),
   cardiomyopathies, mitral valve prolapse, HHT (due to pulmonary
   AVMs).
2. Arterial wall abnormalities.
   (a) Dissection—may be traumatic (including nonaccidental injury), spontaneous, or secondary to Marfan syndrome, Ehlers-Danlos syndrome or homocystinuria.
   (b) Vasculitis/vasculopathy—e.g. due to Moyamoya disease, fibromuscular dysplasia (also vessel stenoses and saccular dilatations, intracranial aneurysms), NF1, Kawasaki, SLE and sarcoidosis.
   (c) Reversible cerebral vasoconstriction syndrome—due to vasospasm, presents with ‘thunderclap’ headache (adolescents > children). Can cause watershed infarcts. Associated with pregnancy (including preeclampsia and
   puerperium) , drugs (e.g. cocaine and amphetamines) and migraine.
3. Cerebral venous sinus thrombosis—pregnancy, postpartum, oral
   contraceptive pill, skull base/intracranial sepsis, IBD, SLE, Behçet’s
   disease and malignancy
4. Infection—purulent meningitis may cause arterial and venous strokes. Viral infection can cause a vasculitis, usually of the proximal MCA, leading to infarction of the basal ganglia with sparing of the cortical territories.
5. Blood disorders—sickle cell anaemia, polycythaemia, protein C and S deficiency and antiphospholipid syndrome.
6. MELAS—Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episodes.
7. Idiopathic—in many cases, a cause is not found

Question 124

LARGE HEAD IN INFANCY 11

Answer 124

1. Benign familial macrocephaly—usually associated with parental
   large head and large head circumference at birth.
2. Benign enlargement of subarachnoid space (BESS)—also
   called ‘external hydrocephalus’. Benign, self-limiting. Increased
   risk of subdural haematoma either spontaneously or after minor
   accidental trauma, which may mimic nonaccidental injury.
3. Hydrocephalus.
4. Chronic subdural haematoma.
5. Brain tumours.
6. Neurofibromatosis* type 1.
7. Mucopolysaccharidoses*.
8. Hemimegalencephaly.
9. Leukodystrophy.
   (a) Alexander’s disease—typically involves the frontal lobes
   early in its course.
   (b) Canavan’s disease—typically affects the subcortical arcuate
   fibres, but often involves the entire cerebral white matter.
10. Overgrowth syndromes—e.g. Sotos, Simpson-Golabi-Behmel,
    Beckwith-Wiedemann.
11. Hydranencephaly

Question 125

WIDE CRANIAL SUTURES
>10 mm at birth; >3 mm at 2 years; >2 mm at 3 years
5

Answer 125

1. Raised intracranial pressure—e.g. due to intracranial tumour,
   subdural haematoma or hydrocephalus. Only seen in children
   <10 years
2. Infiltration of sutures—e.g. by neuroblastoma (± skull vault
   lucencies and ‘sunray’ spiculation), leukaemia or lymphoma.
3. Metabolic disease—rickets, hypoparathyroidism, lead toxicity or
   bone dysplasias with defective mineralization (e.g.
   hypophosphatasia).
4. Traumatic diastasis of the sutures.
5. Recovery from illness—rapid rebound growth of the brain
   following chronic illness, deprivational dwarfism, prematurity or
   hypothyroidism

Question 126

MULTIPLE WORMIAN BONES 14

Answer 126

1. Idiopathic.
2. Down’s syndrome*.
3. Pyknodysostosis.
4. Osteogenesis imperfecta.
5. Rickets*.
6. Cleidocranial dysplasia*.
7. Kinky hair (Menkes) syndrome.
8. Hypophosphatasia.
9. Hypothyroidism.
10. Otopalatodigital syndrome.
11. Primary acroosteolysis (Hajdu-Cheney syndrome).
12. Pachydermoperiostosis.
13. Gerodermia osteodysplastica—see Section 14.12.
14. Progeria.

Question 127

CRANIOSYNOSTOSIS

Primary craniosynostosis 7

Answer 127

1. Sagittal synostosis—elongated narrow ‘boat-shaped’ skull
   (scaphocephaly).
2. Unilateral coronal synostosis—oblique appearance of the
   craniofacial structures (frontal plagiocephaly) with harlequin orbit.
3. Bilateral coronal synostosis—‘short head’ (brachycephaly), often
   seen with synostosis of other sutures.
4. Metopic synostosis—triangular-shaped head (trigonocephaly) with
   orbital hypotelorism.
5. Unilateral lambdoid synostosis—asymmetric occipital
   plagiocephaly.
6. Bilateral lambdoid synostosis—occipital plagiocephaly with
   flattened occiput. Beware postural flattening of the occiput due to
   infants being placed to sleep on their backs (no sutural fusion in
   these cases).
7. Cloverleaf skull—‘trilobular skull’ due to synostosis of multiple
   paired sutures

Question 128

CRANIOSYNOSTOSIS

Syndromic craniosynostosis

Answer 128

Most commonly seen in acrocephalosyndactylies (e.g. Apert,
Carpenter and Pfeiffer syndromes). Each syndrome exhibits
synostosis of multiple sutures with severe calvarial and facial
malformations. Crouzon syndrome differs in that there is no
syndactyly

Question 129

CRANIOSYNOSTOSIS

Secondary 5

Answer 129

1. Brain damage or malformation—following hypoxic ischaemic
   encephalopathy, holoprosencephaly, microcephaly.
2. Iatrogenic—shunted hydrocephalus.
3. Metabolic—rickets, hyperthyroidism, hypophosphatasia.
4. Inborn errors of metabolism—Hurler and Morquio syndromes.
5. Haematological disease—thalassaemia and sickle cell.

Question 130

CYSTIC LESIONS ON CRANIAL US IN
NEONATES AND INFANTS
Normal variants 2

Answer 130

1. Coarctation of the lateral ventricles—aka connatal cysts: small
   cysts at the superolateral margin of the frontal horns.
2. Cavum septum pellucidum/vergae/velum interpositum—
   common, particularly in premature neonates

Question 131

CYSTIC LESIONS ON CRANIAL US IN
NEONATES AND INFANTS
Infratentorial cysts 3

Answer 131

1. Mega cisterna magna—as an isolated finding, probably a normal
   variant. Intact vermis.
2. Dandy-Walker malformation/variant—vermian hypoplasia +
   cystic dilatation of posterior fossa in communication with the
   fourth ventricle.
3. Arachnoid cyst—one-quarter occur in the posterior fossa, most
   commonly retrocerebellar

Question 132

CYSTIC LESIONS ON CRANIAL US IN
NEONATES AND INFANTS
Supratentorial cysts 6

Answer 132

1. Subependymal cysts—located in subependymal region around
   the caudothalamic notch. Most commonly represent previous
   germinal matrix haemorrhage. May be congenital, probably
   reflecting germinolysis, particularly in association with CMV
   infection.
2. Choroid plexus cysts—usually located within body of choroid
   plexus. Weak markers of aneuploidy, particularly if large and
   bilateral. No clinical significance if detected after birth.
3. Cystic periventricular leukomalacia—white matter necrosis in
   preterm infant. Hyperechoic lesions dorsal and lateral to external
   angles of lateral ventricles, developing into cysts in severe cases.
4. Porencephalic cyst—an area of cystic encephalomalacia filled with
   CSF, often following haemorrhage or infection, communicating
   with the ventricular system.
5. Arachnoid cyst—most commonly in the sylvian fissure, usually
   incidental. Suprasellar cysts are more frequently symptomatic.
6. Vein of Galen malformation—not a cyst, but may appear so on
   US. Colour Doppler flow confirms.

Question 133

DISORDERS OF NEURONAL MIGRATION

5

Answer 133

1. Agyria-pachygyria—poorly formed gyri and sulci, the former
   being more severe. Focal pachygyria may cause focal epilepsy.
   Polymicrogyria may coexist with pachygyria. Pachygyria may also be seen in Zellweger syndrome (germinolytic cysts, polymicrogyria in perisylvian, frontal pachygyria) and prenatal CMV infection.
   Extreme cases with a smooth brain = lissencephaly. Complete
   lissencephaly = agyria. Several distinct forms.
   (a) Type I lissencephaly—small brain with few gyri; smooth,
   thickened four-layer cortex resembling that of a 13-week fetus
   with diminished white matter and shallow vertical sylvian
   fissures (‘figure-of-eight’ appearance on axial images) ±
   agenesis of corpus callosum. Severe mental retardation,
   diplegia, seizures, microcephaly and limited survival. Some
   infants have specific dysmorphic features: Miller-Dieker
   syndrome and Norman-Roberts syndrome.
   (b) Type II lissencephaly (Walker-Warburg syndrome)—smooth
   cobblestone cortex, cerebellar hypoplasia, vermian aplasia and
   hydrocephalus (in 75%) due to cisternal obstruction by
   abnormal meninges or aqueduct stenosis. Eye abnormalities
   including microphthalmia and buphthalmos (enlarged globe) due to increased
   pressure and cataract.
2. Polymicrogyria—the neurons reach the cortex but are distributed
   abnormally. Macroscopically the surface of the brain appears as
   multiple small bumps. Localized abnormalities are more common
   than generalized and often involve arterial territories, especially the
   MCA. Most common location is around the sylvian fissure. The
   cortex is isointense to grey matter but in 20% the underlying
   white matter has high T2 signal. Linear flow voids, due to
   anomalous venous drainage, may be present. Polymicrogyria may
   be present in the vicinity of a porencephalic cyst, and may be
   associated with heterotopic grey matter, agenesis of corpus
   callosum or signs of fetal infection (e.g. intracranial calcification).
   The majority have mental retardation, seizures and neurological
   signs.
3. Schizencephaly—clefts that extend through the full thickness of
   the cerebral mantle from ventricle to subarachnoid space. The cleft
   is lined by heterotopic grey matter and microgyria, indicating that
   it existed prior to the end of neuronal migration. Unilateral or
   bilateral (usually asymmetrical) and usually near the sylvian fissure.
   May be associated with absence of the septum pellucidum or, less
   commonly, dysgenesis of the corpus callosum. Variable clinical
   manifestations, from profound retardation to isolated partial
   seizures.
4. Heterotopic grey matter—collections of neurons in a
   subependymal location, i.e. at the site of the germinal matrix or
   arrested within the white matter on their way to the cortex.
   Isointense to normal grey matter on all imaging sequences.
   Nodules or bands, ± mass effect. Often a part of complex
   malformation syndromes, or when isolated, may be responsible for
   focal seizures (amenable to surgical treatment)
5. Cortical dysplasia—focal disorganization of the cerebral cortex. A
   single enlarged gyrus resembling focal pachygyria. Usual
   presentation is with partial epilepsy.

Question 134

SUPRATENTORIAL TUMOURS

IN CHILDHOOD 10

Answer 134

1. Hemispheric astrocytoma—solid ± necrotic centre, or cystic with
   a mural nodule. Usually large at presentation and can involve
   basal ganglia and thalami. Most are low grade. Enhancement
   with contrast medium does not correlate with histological grade.
   Associated with NF1.
2. Craniopharyngioma—>50% of all craniopharyngiomas occur in
   children (8–14 years). Cystic/solid partially calcified suprasellar
   mass presenting with headache, visual disturbance and endocrine
   abnormalities.
3. Optic pathway glioma—low grade but infiltrative pilocytic
   astrocytomas associated with NF1. Solid enhancing tumours that
   extend along the length of the anterior optic pathways and may
   invade adjacent structures (e.g. hypothalamus) and extend
   posteriorly into the optic tracts and radiations.
4. Giant cell subependymal astrocytoma—occurs in tuberous
   sclerosis; slow-growing partially cystic, partially calcified tumour
   located at the foramen of Monro. Presents with obstructive
   hydrocephalus.
5. Germ cell tumours—germinoma and teratoma.
6. Primitive neuroectodermal tumour (PNET)—large
   heterogeneous hemispheric mass presenting in neonates and
   infants. Necrosis, haemorrhage and enhancement are common.
7. Dysembryoplastic neuroepithelial tumour (DNET)—benign
   cortical tumour often presenting with seizures. Cortical
   (temporal) mass, usually small ± internal cysts and calcification.
8. Ganglioglioma—well-defined peripheral tumour that often
   presents with seizures. Cystic tumour with mural nodule ±
   calcification.
9. Choroid plexus papilloma—presents in young children with
   hydrocephalus. Most occur in the atrium of the lateral ventricle
   (fourth ventricle in adults) and appear as a well-defined multilobulated avidly enhancing intraventricular mass ±
   calcification. Invasion of brain suggests choroid plexus
   carcinoma.
10. Ependymoma—often in the frontal lobe adjacent to the frontal
    horn, but not usually intraventricular

Question 135

INFRATENTORIAL TUMOURS

IN CHILDHOOD 5

Answer 135

1. Cerebellar astrocytoma—most common posterior fossa tumour in
   children ≥5 years. Vermis (50%), hemispheres (20%) or both
   (30%). Calcification in 20%. Large mass displacing (or invading)
   the fourth ventricle. 80% are juvenile pilocytic astrocytomas with
   an excellent prognosis. 50% are cystic with an enhancing mural
   nodule. 40% are solid with central necrosis. 10% are purely solid
   (usually smaller than the other types). Usually no restricted
   diffusion.
2. Medulloblastoma—most common posterior fossa tumour in
   children <5 years. Short history (aggressive). 80% located in the
   vermis, often extending into the fourth ventricle through its roof;
   30% extend into the brainstem. Moderately well-defined mass,
   slightly hyperdense to surrounding cerebellum on CT + rim of
   oedema. Calcification in 10%. Small cystic or necrotic areas can be
   seen. Variable enhancement. Heterogeneous T2 signal on MRI.
   Marked restricted diffusion is typical. Tumour disseminates through
   CSF into the subarachnoid space (including spinal canal) and
   ventricular system. Extracranial metastases to bone, lymph nodes
   or soft tissues.
3. Ependymoma—15% of posterior fossa tumours. Usually a long
   clinical history. Most commonly arises from the floor of the fourth
   ventricle. On CT, typically an iso- or hyperdense mass with
   punctate calcifications, small cysts and heterogeneous
   enhancement. Calcification in a fourth ventricular mass or adjacent
   to the fourth ventricle = ependymoma. Heterogeneous on MRI,
   with less restricted diffusion than medulloblastoma. Tumour
   extension through the foramina of Luschka or Magendie is
   characteristic.
4. Brainstem glioma—insidious onset because of its location and
   tendency to infiltrate cranial nerve nuclei and long tracts without
   producing CSF obstruction until late. Four subgroups: medullary,
   pontine (most common), mesencephalic and those associated with
   NF1 (slower progression). Tumours may also be diffuse (>50%–
   75% of the brainstem in the axial plane, most common in pons)
   or focal (<50%, most common in tectal plate). Calcification rare.
   Typically T2 hyperintense on MRI, with no/minimal restricted
   diffusion or enhancement.
5. Atypical teratoid/rhabdoid tumour (ATRT)—rare but aggressive,
   with high potential for CNS dissemination. Usually in children <3
   years. On MRI, ATRT often shows heterogeneous signal with
   diffusion restriction, similar to medulloblastoma, but has a higher
   propensity for calcification (~50%), haemorrhage, necrosis and
   cystic change.

Question 136

INTRAVENTRICULAR MASS IN CHILDREN

Solid mass Lateral ventricles 11

Answer 136

1. Choroid plexus papilloma/carcinoma—see Section 14.72.
2. Astrocytomas—usually arise from subependymal tissue and
   protrude into ventricle.
3. Ependymoma—less common than in fourth ventricle.
4. Primitive neuroectodermal tumour—see Section 14.72.
5. Meningioma—rare in children except in NF2.
6. Choroid plexus enlargement—NF1, Sturge-Weber.
7. Teratoma.
8. Arteriovenous malformation—enlarged draining veins.
9. Subependymal heterotopia—nodules of ectopic grey matter.
10. Metastatic seeding—e.g. medulloblastoma, ependymoma.
11. ATRT - atypical teratoid/rhabdoid tumour

Question 137

IINTRAVENTRICULAR MASS IN CHILDREN

Solid mass Foramen of Monro 2

Answer 137

1. Subependymal giant cell astrocytoma—see Section 14.72.
2. Central neurocytoma—well-defined heterogeneous mass arising
   from septum pellucidum close to foramen of Monro. Often
   contains calcification and cystic change.

Question 138

INTRAVENTRICULAR MASS IN CHILDREN

Solid mass Third ventricle 7

Answer 138

1. Craniopharyngioma—arises from the suprasellar region (see
   Section 14.72); may mimic a third ventricle mass if large.
2. Glioma—hypothalamic or chiasmatic pilocytic astrocytomas.
3. Germinoma—pineal or suprasellar; see Chapter 13.
4. Teratoma—usually posterior, in the pineal region.
5. Langerhans cell histiocytosis*—arises from the floor of the third
   ventricle or suprasellar region.
6. Choroid plexus papilloma—see Section 14.72.
7. Metastatic seeding

Question 139

INTRAVENTRICULAR MASS IN CHILDREN

Solid mass Fourth ventricle 5

Answer 139

1. Medulloblastoma—see Section 14.73.
2. Ependymoma—see Section 14.73.
3. Choroid plexus papilloma—see Section 14.72.
4. Exophytic brainstem/cerebellar glioma—see Section 14.73.
5. ATRT

Question 140

INTRAVENTRICULAR MASS IN CHILDREN

Cystic mass 5

Answer 140

1. Choroid plexus cyst/xanthogranuloma—typically in the trigone
   of the lateral ventricles, often bilateral. Usually incidental.
2. Colloid cyst—characteristic location in the anterosuperior aspect of
   the third ventricle, close to the foramina of Monro ± obstructive
   hydrocephalus. Typically contains proteinaceous material,
   appearing hyperdense on unenhanced CT and causing variable
   (but homogeneous) T1 and T2 signal on MRI. No enhancement.
3. Intraventricular simple cysts—e.g. ependymal cyst, arachnoid
   cyst. Follows CSF on all MRI sequences, thin/imperceptible wall
   and no enhancement. Distorts ventricle outline when large (may
   be the only sign of its presence).
4. Cysticercosis*—appearance varies depending on stage. Often
   causes ventriculitis leading to aqueduct stenosis and
   hydrocephalus.
5. Hydatid cyst—rare