Pituitary adenoma with craniopharyngioma component.

Neoplasms consisting of pituitary adenoma and craniopharyngioma components are rare and are being increasingly recognized. Their histogenesis is not clear. Most represent collision tumors; others are difficult to assess. Here, we describe a pituitary adenoma with an intermingled craniopharyngioma component, without forming 2 distinct mass lesions or histologic delineation. Areas that suggest a transition between the 2 components were also present. It was clinically a nonfunctioning adenoma, which was also negative for pituitary hormones by immunohistochemistry. Its histogenesis and implications are discussed with a review of the literature.