Calcified cystic pituitary prolactinoma.

Abstract An unusual cystic pituitary prolactinoma in a 20-year-old man is described. The tumor was roentgenographically calcified. Ultrastructurally, the calcium deposits were found within the cytoplasm of tumor cells, extracellular spaces and blood vessels. The mechanism of intratumoral calcification is discussed in relation to degeneration of neoplastic cells and reparative process.