Craniopharyngioma, microscopic: On the left side of this slide of a craniopharyngioma the characteristics of the neoplastic elements of this tumor are seen. The cells are small and have an epithelial appearance. Numerous microcystic spaces are formed. On the right side of the slide are additional structures frequently encountered in craniopharyngiomas. These include hyalinized structures that are frequently calcified, collagen, fibroblasts, foreign body giant cells, and sometimes cholesterol clefts.