CNS Tumors

Peds CNS Tumors: Overview - Brainy Bunch Intro

• Epidemiology:
  • Most common solid tumors in children.
  • 2nd most common pediatric malignancy overall (after leukemia).
• Common Locations:
  • Younger children (<2 yrs): Infratentorial (posterior fossa) > Supratentorial.
  • Older children/adolescents: Supratentorial predominance ↑.
• Key Predisposing Genetic Syndromes:
  • Neurofibromatosis Type 1 (NF1)
  • Neurofibromatosis Type 2 (NF2)
  • Von Hippel-Lindau (VHL)
  • Li-Fraumeni Syndrome (TP53)
  • Tuberous Sclerosis Complex (TSC)

⭐ Brain tumors are the most common solid tumors in children and the second most common pediatric malignancy after leukemia.

Infratentorial Tumors - Posterior Fossa Foes

• Most common site for pediatric brain tumors. Key types:

-   Located in pons.
-   Highly aggressive, infiltrative.
-   Poor prognosis. 📌 Pons + Palsies = Poor Prognosis.

⭐ Medulloblastoma, the most common malignant pediatric brain tumor, typically arises in the cerebellar vermis and can disseminate via CSF (drop metastases), often presenting with signs of hydrocephalus.

Supratentorial Tumors - Cerebral Command Crashers

• Craniopharyngioma:
  • Rathke's pouch origin.
  • Suprasellar calcification, cystic ('machine oil' fluid).
  • Endocrine (↓GH), visual (bitemporal hemianopsia).

  ⭐ Craniopharyngiomas classically show suprasellar calcification on imaging and are notorious for causing endocrine dysfunction (e.g., growth hormone deficiency) and bitemporal hemianopsia.

• Germ Cell Tumors (GCTs):
  • Pineal/suprasellar location.
  • Markers: ↑AFP, ↑$\beta$-hCG.
  • Germinoma (common, radiosensitive), teratoma.
• Supratentorial Astrocytomas/Gliomas:
  • Common pediatric brain tumors.
  • Varied grades (WHO I-IV); seizures, focal deficits, ↑ICP.
  • Incl. Pilocytic (optic pathway), GBM. oka

Peds CNS Tumors: Dx & Tx - Brain Battle Plan

• Clinical Presentation:
  • Raised Intracranial Pressure (ICP): Morning headache, vomiting (often projectile, unrelated to meals), papilledema, lethargy.
  • Focal Neurological Deficits: Ataxia, cranial nerve palsies, seizures, endocrinopathy (e.g., diabetes insipidus, growth failure).
• Diagnosis:
  • MRI with gadolinium contrast: Gold standard imaging.
  • CSF cytology: For suspected leptomeningeal dissemination.
  • Biopsy: Essential for histological diagnosis and grading.
• Management Principles:
  • Maximal safe surgical resection.
  • Radiotherapy (RT): Adjuvant; avoid/delay in children < 3 years due to neurocognitive sequelae.
  • Chemotherapy: Adjuvant, neoadjuvant, or salvage; specific protocols vary by tumor type.

⭐ The 'triad' of morning headaches, vomiting (often projectile and unrelated to meals), and lethargy strongly suggests raised intracranial pressure (ICP), a common presentation of pediatric brain tumors.

High‑Yield Points - ⚡ Biggest Takeaways

• CNS tumors: most common solid tumors in children; infratentorial more frequent.
• Pilocytic astrocytoma: most common pediatric brain tumor; often cerebellar, Rosenthal fibers.
• Medulloblastoma: most common malignant; cerebellar (vermis); Homer Wright rosettes, radiosensitive.
• Craniopharyngioma: from Rathke's pouch; suprasellar calcification; visual defects.
• Ependymoma: often in 4th ventricle; causes hydrocephalus; perivascular pseudorosettes.
• Key symptoms: morning headache, vomiting, ataxia, papilledema.
• Brainstem gliomas (e.g., DIPG) have a dismal prognosis.