Medulloblastomas are the most common malignant pediatric brain tumor, accounting for 15–20% of pediatric brain tumors and 30–55% of posterior fossa tumors (13, 19, 20).
The mean age at presentation is 5–7 years, and 80% of patients are younger than 15 years (13).
Medulloblastomas are more common in males than females, with the male:female ratio ranging from 1.4:1 to greater than 2:1, depending on the series (3, 8).
None known: No environmental factors have been definitively associated with medulloblastoma incidence (15).
Relationships to Other Disease States and Syndromes
Gorlin’s syndrome: 5% incidence of medulloblastoma, also associated with multiple nevoid and basal cell carcinomas, multiple skeletal and cutaneous anomalies, hydrocephalus, calcification of the dura, and developmental delay (15).
Turcot’s syndrome: Known also as multiple familia polyposis, associated with colorectal polyps and colorectal carcinoma (15).