SIDS And Infant tumors Flashcards
(28 cards)
What is SIDS?
•Sudden Infant Death Syndrome (SIDS) is the sudden death of an infant under 1 year of age, which remains unexplained after a thorough case investigation, including the performance of a complete autopsy, examination of the death scene and review of the clinical history.
Causes of death
- NEONATE (0-4 WEEKS): CONGENITAL, PREMATURITY
- UNDER ONE YEAR: CONGENITAL, PREMATURITY/WEIGHT, SIDS
- 1-4 YEARS: ACCIDENTS, CONGENITAL, TUMORS
- 5-14 YEARS: ACCIDENTS, TUMORS, HOMICIDES
- 15-24 YEARS: ACCIDENTS, HOMICIDE, SUICIDE
Epidemiology and facts about SIDS
- 90% of SIDS deaths before 6 months of age
- Most SIDS deaths happen when babies are between 2 months and 4 months of age.
- Seasonal trend: there are more SIDS deaths in winter months.
- More male babies die of SIDS.
- Unaccustomed tummy sleeping increases risk as much as 18-fold.
Morphology of SIDS
•SIDS is a diagnosis of exclusion
•Non-specific autopsy findings
–Multiple petechiae (thymus, pleura, epicardium)
–Pulmonary congestion ± pulmonary edema
(These may simply be agonal changes as they are found in non-SIDS deaths also)
-Histological signs of recent infections in the upper respiratory system
Pathogenesis of SIDS
•Delayed development of “arousal” and cardiorespiratory control theory
•Abnormalities in the serotonin-dependant signaling in the brain stem
•Normally activation of laryngeal chemoreceptors causes inhibition of cardiorespiratory reflex
•Respiratory infections increase activity of Laryngeal Chemoreceptors – hypoxia- death
serotonergic (5-HT) system of the medulla is implicated in “arousal” responses
Common features of pediatric tumors
- Both type of tumors are present: benign and malignant
- Benign tumors in children more common than malignant but do not have statistical impact on mortality rate
- Only 2% of all malignant tumors occur in infancy or childhood
- Pediatric tumors are the second leading natural cause of death under age 14 (accidents are #1)
- Brain tumors and leukemia/lymphoma account for about two-thirds
- Pediatric and adult cancers are different (epithelial origin in adults, mesenchymal origin in children)
Benign tumors
- Hemangiomas
- Lymphatic Tumors
- Fibrous Tumors
- Teratomas (also can be malignant)
•Benign tumor of blood vessels
- Are the most common tumor of infancy
- Two types: cavernous and capillary
- Locations: usually on skin, especially face and scalp
- Irregular red-blue masses (port-wine stains)
- Regress spontaneously in many cases before 5 years old
- Sometimes are part of Von Hippel-Lindau (VHL) disease ( CNS hemangioblastomas, pheochromocytoma, renal cell carcinoma + pancreatic cysts)
Hemangioma
- Benign tumor of blood vessels
- Are the most common tumor of infancy
- Two types: cavernous and capillary
- Locations: usually on skin, especially face and scalp
- Irregular red-blue masses (port-wine stains)
- Regress spontaneously in many cases before 5 years old
- Sometimes are part of Von Hippel-Lindau (VHL) disease ( CNS hemangioblastomas, pheochromocytoma, renal cell carcinoma + pancreatic cysts)
Congenital-infantile fibrosarcoma
Excellent prognosis, that is why it’s here
- A vascular birthmark that is not behaving as expected - it’s growing rapidly; it’s firm; it’s infiltrative, especially in a distal location like the hands or feet
- Result of unique fusion oncogene ETV6-NTRK3 – is an important diagnostic marker
Lymphatic Benign Tumors (Cystic Hygromas)
- Lymphangiomas: cystic or cavernous types, MC location deep regions of the neck, axilla, mediastinum.
- Lymphangiectasis: result in diffuse swelling of part or all extremity
Teratomas
•Composed of cells derived from more than one germ layer, usually all three
•Can be benign (75%), intermediate potential and malignant (12%)
•Two peaks of incidence: 2 years old (mostly benign) and 16-18 years old (mostly malignant)
•Sacrococcygeal teratomas:
–most common childhood teratoma
–4 times more common in boys than girls
Other locations: testis, ovaries, mediastinum, retroperitoneum, neck, head
DIFFERENCES
IN PEDIATRIC CANCER vs ADULT CANCER
- Site of origin different (mesenchymal)
- Type – sarcomas, “blastomas,” small round blue cell tumors
- Bulk typically greater but no cachexia
- Prognosis often better, spontaneous regression, high sensitivity to antineoplastic therapy
- Neonatal tumors – tend to be less aggressive
- Prevalence of familial and genetic aberrations
INCIDENCE AND TYPES of MALIGNANT TUMORS IN CHILDREN
•Children younger than 5 years old:
- Leukemias (Acute Lymphoblastic)
- Brain Tumors (Posterior Fossa Medulloblastomas, Astrocytomas)
- Lymphoma
- Nephroblastoma (Wilms Tumor)
- Neuroblastoma
- Retinoblastoma
- Hepatoblastoma, etc
Histological difference from adult malignant tumors
- Child tumors are not pleomorphic-anaplastic structure but embryonal
- BLASTOMA – A neoplasm composed of embryonic cells derived from the blastema of an organ or tissue [Gr. BLASTOS = germ]
- Primitive neuroectodermal tumors (PNETs) are a group of highly malignant tumors composed of small round cells of neuroectodermal origin that affect soft tissue and bone.
Important blastomas
Nephroblastoma (Wilms Tumor) – Kidney
Neuroblastoma – adrenal medulla and sympathetic nervous system
Hepatoblastoma – liver
Pleuropulmonary blastoma – lung/pleura
Pancreatoblastoma – pancreas
Retinoblastoma – neural retina
Medulloblastoma – cerebellum
Neuroblastoma
- Tumor derived from primordial neural crest cells
- Arise in the adrenal medulla, but also along the sympathetic chain ganglia (or dorsal root ganglia) anywhere from the base of the skull to the pelvis
- Most common extracranial solid malignant tumor of childhood
- Most patients <2 years old, Median age at diagnosis is 22 months
- May be congenital (1-2%)
- May present with mass only or constitutional symptoms
- Commonly metastatic at presentation – may involve bizarre sites (orbits, skin)
- Caused by amplification of N-MYC gene
- 90% secrete catecholamines but hypertension rare
What paraneoplastic syndrome is specific for neuroblastoma
Opsoclonus-Myoclonus Syndrome
What laboratory parameters allow to confirm the diagnosis of NB?
Elevated levels of Norepinephrine, Vanillyl mandelic acid, Homovanillic Acid (HVA), and Dopamine
Morphology of neuroblastoma
•Small round blue cell tumor
–neuropil formation
–rosette formation (Homer-Wright Rosettes)
–immunochemistry – neuron specific enolase, neurofilament
–EM – secretory granules (catecholamine)
•Usual features of anaplasia
–high mitotic rate is unfavorable
–evidence of Schwann cell or ganglion differentiation favorable
•Other prognostic predictors are used by pathologists and oncologists
Neuroblastoma Stage IV S (Special)
- Metastases limited to liver, skin, bone marrow
- Patients usually <1 year old and with small primaries
- Have an unusually good prognosis compared with stage IV
Wilm’s Tumor (nephroblastoma)
- Most common malignant kidney tumor in children (1:10 000 children affected)
- About 500 new cases per year in U.S.
- Synchronous - involvement of both kidneys
- Metachronous- sequential involvement of kidneys
- Peak age 2-4 years
Conditions associated with Wilm’s tumor: WAGR syndrome
- 10% of Wilms Tumors associated with several types of congenital malformations – they called syndromic Wilms Tumors
- WAGR syndrome (Wilms tumor , Aniridia, Genital anomalies, Retardation) – result of deletion of 11p13
- 11p13 contains genes WT1 and Pax6. WT1 is transcriptional factor positive regulator of differentiation (oncosupressor)
Condition associated with Wilm’s tumor: Deny’s Drash syndrome
•Denys-Drash syndrome (male pseudohermaphroditism, early onset nephropathy due to mesangial sclerosis, Wilms Tumor) •Patients also have increased risk development of gonadoblasomas •Patients have mutation in WT1 gene located on 11p
