PAEDIATRICS Flashcards

Question

PERIOSTEAL REACTIONS—BILATERALLY | SYMMETRICAL IN CHILDREN

Answer 1

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)

Answer 2

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.

Answer 3

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

Answer 4

1. Osteopetrosis. | 2. Pyknodysostosis

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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*

Answer 9

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

Answer 10

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.

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

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

Answer 15

1. Thalassaemia*.

Answer 16

. Gaucher disease*. | 2. Niemann-Pick disease*.

Answer 17

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

Answer 18

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*.

Answer 19

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

Answer 20

1. Trauma. | 2. Infection—low-grade osteomyelitis mimics osteitis pubis

Answer 21

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.)

Answer 22

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

Answer 23

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

Answer 24

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

Answer 25

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

Answer 26

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).

Answer 27

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

Answer 28

. 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

Answer 29

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

Answer 30

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)

Answer 31

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

Answer 32

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)

Answer 33

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

Answer 34

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

Answer 35

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.

Answer 36

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.

Answer 37

• 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.

Answer 38

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

Answer 39

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.

Answer 40

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

Answer 41

1. Laryngeal polyp, papilloma or cyst

Answer 42

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.

Answer 43

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

Answer 44

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)

Answer 45

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).

Answer 46

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

Answer 47

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.

Answer 48

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

Answer 49

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.

Answer 50

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.

Answer 51

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.

Answer 52

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

Answer 53

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).

Answer 54

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

Answer 55

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

Answer 56

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.

Answer 57

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

Answer 58

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

Answer 59

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

Answer 60

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.

Answer 61

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

Answer 62

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.

Answer 63

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

Answer 64

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

Answer 65

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

Answer 66

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

Answer 67

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

Answer 68

1. Renal tumours 2. Hydronephrosis 3. Cysts

Answer 69

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

Answer 70

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.

Answer 71

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.

Answer 72

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

Answer 73

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

Answer 74

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

Answer 75

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) ```

Answer 76

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

Answer 77

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

Answer 78

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.

Answer 79

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

Answer 80

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

Answer 81

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.

Answer 82

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

Answer 83

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

Answer 84

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

Answer 85

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

Answer 86

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

Answer 87

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

Answer 88

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

Answer 89

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

Answer 90

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.

Answer 91

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. 5. Urethral stricture—posttraumatic strictures (e.g. instrumentation or catheterization) are most commonly at the penoscrotal junction. 6. 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. 7. 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. 8. Prune-belly and megacystis-microcolon syndromes. 9. Calculus or foreign body. 10. Meatal stenosis—males only; usually a clinical diagnosis, but may be detected on MCUG; voiding images should include the meatus (external urethral opening). 11. Phimosis—clinical diagnosis

Answer 92

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

Answer 93

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.

Answer 94

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.

Answer 95

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.

Answer 96

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)

Answer 97

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

Answer 98

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)

Answer 99

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

Answer 100

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

Answer 101

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

Answer 102

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.

Answer 103

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

Answer 104

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

Answer 105

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.

Answer 106

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

Answer 107

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

Answer 108

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.

Answer 109

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.

Answer 110

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

Answer 111

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.

Answer 112

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

Answer 113

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.

Answer 114

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

Answer 115

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

Answer 116

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

PAEDIATRICS Flashcards

(140 cards)