NON-FUNCTIONAL PITUITARY TUMORS: A MISLEADING PRESENTATION OF AN INTRASELLAR PLASMACYTOMA.

: Intrasellar plasmacytoma is a rare pituitary tumor, which originates from monoclonal plasma cells in a single lesion. Knowledge of its features comes from case reports only. Here, we present an interesting case of a 77-year-old woman with a presumptive diagnosis of non-functioning pituitary adenoma, as based on both clinical and radiological examinations. Following endoscopic endonasal transsphenoidal surgery, the definitive diagnosis of intrasellar plasmacytoma was made by immunohistochemical analysis of the sellar mass. Intrasellar plasmacytoma is rare, but it should be evaluated in the differential diagnosis of a pituitary mass due to its different therapeutic approach and prognosis, since it can frequently progress to multiple myeloma.