Pigmented primary epithelial tumor of the sella: A report of an intriguing case.

This is a report of an uncommon primary pigmented papillary epithelial tumor of the sella in a 38-year-old man, who presented with clinicoradiological features of pituitary adenoma. Histologically, the tumor showed features reminiscent of choroid plexus papilloma, that is, conspicuous papillary epithelial morphology with presence of intacytoplasmic melanin and no mitotic activity. Immunohistochemically, the tumor was positive for pancytokeratin (AE1/AE3), S-100 protein and CD56, while it was negative for glial fibrillary acid protein, thyroid transcription factor-1, epithelial membrane antigen, other cytokeratins and pituitary hormones. These findings were not typical of any WHO-defined entity and is thus best regarded as a pigmented papillary epithelial tumor of sella of uncertain histogenesis. The present case is a valuable addition to the spectrum of primary pigmented papillary epithelial tumors originating at an unusual location.