i guess it is pilocytic astrocytoma (most common on children on the upper pole of cerebellum, well circumscribed)
pilocytic astrocytoma PILOCYTIC ASTROCYTOMA.... is a benign tumor,usually arise in the cerebellum, near the brainstem, hypothalamic region, or the optic chiasm, but they may occur in any area where astrocytes are present, including the cerebral hemispheres and the spinal cord. These tumors are usually slow growing. The neoplasms are associated with the formation of a single (or multiple) cyst(s), and can become very large.
