Pediatric Tumors

Pediatric Tumors: General Concepts - Tiny Terrors Intro

• Differ from adult tumors: embryonal origin (vs. epithelial), better prognosis, often chemo/radiosensitive.

• Common patterns: often arise from developmental rests; may regress spontaneously (e.g., neuroblastoma).

• Key Genetic Syndromes & Associated Tumors:

  Syndrome	Associated Tumors
  Beckwith-Wiedemann	Wilms tumor, hepatoblastoma, neuroblastoma
  Li-Fraumeni	Sarcomas, brain tumors, leukemia, adrenocortical Ca
  Neurofibromatosis 1 (NF1)	Neurofibromas, optic glioma, pheochromocytoma
  WAGR Syndrome	Wilms tumor, Aniridia, Genitourinary anomalies, mental Retardation
  Denys-Drash Syndrome	Wilms tumor, gonadal dysgenesis, nephropathy

⭐ Small round blue cell tumors (e.g., neuroblastoma, Ewing sarcoma, Wilms tumor, rhabdomyosarcoma, lymphoma/leukemia) are a characteristic group in pediatric oncology.

Neuroblastoma - Adrenal Annihilators

• Origin: Neural crest cells (sympathetic nervous system).
• Sites: Adrenal medulla (most common), paraspinal ganglia.
• Age: Median ~2 years; prognosis significantly better if <18 months.
• Presentation: Abdominal mass (firm, irregular, often crosses midline), opsoclonus-myoclonus syndrome ("dancing eyes, dancing feet"), Horner's syndrome, blueberry muffin rash (skin mets).
• Investigations: ↑ Urine VMA/HVA; MIBG scan (specific uptake); Bone marrow biopsy (staging).
• Staging: INSS / INRGSS systems.
• Prognostic Factors: Age (<18mo favorable), stage (lower better), N-myc amplification (📌 Nasty MYC = poor prognosis), histology (Shimada: favorable/unfavorable).

⭐ Neuroblastoma is known for spontaneous regression, especially in infants <1 year with Stage 4S disease.

Wilms Tumor - Kidney Kidnappers

• Origin: Metanephric blastema (embryonic kidney cells).
• Age: Peak 3-4 yrs; 90% diagnosed < 7 yrs. Usually unilateral.
• Presentation: Asymptomatic abdominal mass (most common; smooth, firm, rarely crosses midline). Hematuria, hypertension (renin ↑), abdominal pain, fever.
• Associated Syndromes:

  Syndrome	Key Features (Gene Defect)
  WAGR	📌 Wilms, Aniridia, GU anomalies, Retardation (11p13, WT1 del)
  Denys-Drash	Gonadal dysgenesis, early nephropathy, Wilms (WT1 mut)
  Beckwith-Wiedemann	Macroglossia, omphalocele, hemihypertrophy, Wilms (11p15.5, WT2)

• Histology: Triphasic: blastemal, epithelial (tubules), stromal. Favorable (FH) vs. Anaplastic (unfavorable; nuclear atypia).
• Staging (NWTS - National Wilms Tumor Study):

⭐ Bilateral Wilms tumor occurs in 5-10% of cases, often has an earlier age of onset, and frequently requires modified treatment protocols including neoadjuvant chemo.

Other Key Pediatric Tumors - Malignant Minis Mix

• Rhabdomyosarcoma (RMS): Most common pediatric soft tissue sarcoma.

  Type	Prognosis	Common Sites
  Embryonal	Better	Head/Neck, GU (e.g., sarcoma botryoides)
  Alveolar	Worse	Extremities, Trunk

• Retinoblastoma: RB1 gene. Signs: leukocoria (white reflex), strabismus.

  ⭐ Leukocoria (white pupillary reflex) is a classic sign of Retinoblastoma.

• Hepatoblastoma: Most common pediatric liver tumor. Marker: ↑ AFP. Assoc: BWS, FAP.
• Bone Sarcomas:
  • Osteosarcoma: Metaphysis, sunburst pattern.
  • Ewing Sarcoma: Diaphysis, onion-skin appearance, small round blue cells.

High‑Yield Points - ⚡ Biggest Takeaways

• Wilms' tumor: Most common pediatric renal mass; linked to WAGR, Denys-Drash, BWS.
• Neuroblastoma: Top extracranial solid tumor; N-myc (poor prognosis); ↑ VMA/HVA; opsoclonus-myoclonus.
• Retinoblastoma: Presents with leukocoria (white reflex); RB1 gene mutation.
• Hepatoblastoma: Main pediatric liver cancer; ↑ AFP; linked to BWS, FAP.
• Rhabdomyosarcoma: Top pediatric soft tissue sarcoma; common in head/neck, GU tract.
• Brain tumors: Most common solid tumors; often infratentorial (e.g., medulloblastoma).