Final answer:
Pilocytic astrocytoma refers to a benign brain tumor in the cerebellum, part of the metencephalon. Surgical resection of the tumor has a high survival rate, with about 90% of patients surviving when 90% of the tumor is removed.
Step-by-step explanation:
The term pilocytic astrocytoma refers to a type of brain tumor that arises from astrocytes, which are star-shaped cells that make up the supportive tissue of the brain. Specifically, this question mentions pilocytic astrocytoma of the cerebellum, an area at the back of the brain that regulates motor control and balance among other functions. The cerebellum is part of the metencephalon, a secondary vesicle of the embryonic brain which will also develop into the pons. The statement 'Resect: ~90% survive' suggests that when approximately 90% of this tumor is surgically removed (resected), there is a survival rate of around 90%. Pilocytic astrocytomas are generally considered to be benign, slow-growing tumors and are classified as Grade I by the World Health Organization, meaning they are less aggressive than higher-grade tumors.