Childhood primary brain tumors

Question 1

Pilocytic (low-grade) astrocytoma

Answer 1

Usually well circumscribed. In children, most often found in posterior fossa (e.g., cerebellum). May be supratentorial. GFAP positive. Benign; good prognosis.

Notes:
Rosenthal fibers - eosinophilic, corkscrew fibers, Cystic + solid (gross).

Question 2

Medulloblastoma

Answer 2

Highly malignant cerebellar tumor. A form of primitive neuroectodermal tumor. Can compress 4th ventricle, causing hydrocephalus. Can send “drop metastases” to spinal cord.

Notes:
Homer-Wright rosettes. Solid (gross), small blue cells (histology). Radiosensitive.

Question 3

Ependymoma

Answer 3

Ependymal cell tumors most commonly found in 4th ventricle. Can cause hydrocephalus. Poor prognosis.

Notes:
Characteristic perivascular pseudorosettes. Rod-shaped blepharoplasts (basal ciliary bodies) found near nucleus.

Question 4

Hemangioblastoma

Answer 4

Most often cerebellar; associated with von Hippel-Lindau syndrome when found with retinal angiomas. Can produce EPO -> 2 degree polycythemia.

Notes:
Foamy cells and high vascularity are characteristic.

Question 5

Craniopharyngioma

Answer 5

Benign childhood tumor, confused with pituitary adenoma (can also cause bitemporal hemianopia). Most common childhood supratentorial tumor.

Notes:
Derived from remnants of Rathke’s pouch. Calcification is common (tooth enamel-like).