Pituitary giant spindle cells oncocytoma - case report

Abstract

Pituitary spindle cell oncocytoma (SCO) is a non-endocrine neoplasm originating in adenohipophysis. It arises from the follicle-stellate cells, and only 17 cases have been published. We reported a rare case of giant SCO in a 59-year-old male who presented with clinical features of hypopituitarism. MRI findings revealed a giant pituitary adenoma. Histologically, tumor formed by homogeneous spindle cells, the tumor cells were immunoreactive to vimentin, FSH, PTTG-1 gene, TTF-1, Fit-1 and Pit-1. In addition, the spindle cells were positive to nestin, vimentin and β-FGF and low Ki67 labeling index. The electro microscopic image reveled numerous and tortuous mitochondria’s and diagnosis of giant spindle cell oncocytoma was given. Conclusion: Histological, immunohistochemical and ultrastructure findings confirmed the diagnosis of spindle cell oncocytoma. In our knowledge, this is the 18th case of its kind in the literature and the first with giant tumor. The biologic characterization of pituitary stem/progenitor and oncocytic cells could also allow a better understanding of the biological basis of some pituitary adenomas and the origin of this tumor.