A WHO Grade 1 astrocytoma which arises in the cerebellum. The tumor is composed of spindle shaped cells with numerous collections of reddish astrocytic fibers called Rosenthal fibers. Over 80% or the cerebellar astrocytomas of childhood are pilocytic. Pilocytic astrocytomas may rarely occur in adults. They are usually treated by surgical resection and in most cases have a favorable prognosis.