Where do pilocytic astrocytomas most commonly occur in children?

• A. Frontal lobe
• B. Cerebellum
• C. Brainstem
• D. Temporal lobe

Answer: (B)

Pilocytic astrocytomas most commonly arise in the cerebellum in children. They are typically slow-growing, WHO grade I tumors that often appear as a cyst with a solid, enhancing mural nodule on MRI. The cerebellar (posterior fossa) location explains presenting symptoms such as gait disturbance and ataxia, and can lead to hydrocephalus if the fourth ventricle is compressed. While they can occur in other brain regions, those sites—frontal or temporal lobes, or brainstem—are much less common for this tumor in kids. The usual treatment is surgical resection, and achieving gross total resection often results in cure, with radiotherapy generally avoided in pediatric patients due to long-term side effects.