T-cell lymphoblastic lymphoma/leukemia presenting as a pituitary mass lesion: a case report and review of the literature.

We present a rare case of primary T-cell lymphoblastic lymphoma of the pituitary gland. A 58-year-old woman presented with headaches, right-sided ptosis and cranial nerve III palsy. She subsequently developed polyuria, polydipsia, and hyperglycemia and was found to have hypopituitarism. MRI revealed a large, heterogeneously enhancing intrasellar/suprasellar lesion displacing the optic chiasm and extending into the right cavernous sinus. Radiologically, these findings were thought to represent an invasive pituitary adenoma. Pterional craniotomy was performed with subtotal tumor resection. Histopathological examination revealed a T-cell lymphoblastic lymphoma/leukemia (T-LBL) admixed with pituitary corticotrophic cell hyperplasia. CT scans of the chest, abdomen and pelvis showed no evidence of systemic disease. Analysis of peripheral blood and bone marrow, including flow cytometry, demonstrated no involvement by T-LBL. Follow-up MRI of the spine revealed abnormalities in the distal thoracic spinal cord and conus medullaris, raising suspicions of leptomeningeal dissemination. Only five case reports of T-cell primary pituitary lymphoma (PPL) have been previously described, four of which were associated with hypopituitarism and/or concurrent pituitary adenoma. We present the first report of a T-cell PPL associated with adenohypophyseal hyperplasia and the third documented occurrence of a primary pituitary T-LBL.