CYSTIC PROLACTINOMA - A VARIANT OF TRANSITIONAL CELL TUMOR OF THE PITUITARY

Pituitary tumors with features of Rathke''s cleft cysts and adenohypophysial adenomas are extremely rare and have been termed transitional cell tumors. The ultrastructural features of 1 of these tumors has been reported, demonstrating cells with features transitional between those of adenohypophysial cells and Rathke''s cleft cells, along with other cells with the distinctive features of either cell type. A [human] case of a prolactin-secreting transitional cell tumor with similar light-microscopic and ultrastructural features is reported. The transitional cells in this case exhibited abundant intracellular mucin production. This represents a variant of the transitional cell tumor of the pituitary gland.