Astrocytoma, cystic, low-grade: Another type of low-grade astrocytoma is astrocytoma of the cerebellum. Cerebellar astrocytomas are confined almost exclusively to childhood. They may or may not be cystic. In this example the major portion of the mass is gelatinous cystic material produced by the tumor. Most of the neoplasm is located in the upper central portion of the slide. Not only is the cystic mass fairly well defined, but the tumor also is sharply circumscribed, in contrast to the infiltrative mass seen in the previous slide.