Squash smear cytology of pituitary granular cell tumor: A case report and review of literature with special emphasis on cytological differential diagnosis in pituitary region

Neurohypophysis granular cell tumor (NGCT) is a rare entity and is classified under thyroid transcription factor 1 (TTF-1) expressing tumors of pituitary. It is considered as an uncommon differential during sellar and suprasellar mass evaluation. Its intraoperative squash cytology is distinct and has rarely been reported in literature. A 65-year-old female presented with reduced vision of right eye and history of seizures. Radiological findings revealed a sellar/suprasellar mass with mass effect on optic chiasma. Intraoperative squash neurocytology examination showed a spindle cell lesion with abundant granular cytoplasm in tumor cells. Subsequent histopathology and immunohistochemistry confirmed the diagnosis of granular cell tumor. Granular cell tumor remains one of the sellar/suprasellar surprises. Its intraoperative neurocytology is unique and should be considered while evaluating a sellar/suprasellar mass. A case of sellar granular cell tumor with its intraoperative squash cytology, histopathology along with a review of literature is being presented with special emphasis on cytological differential diagnosis in pituitary region.

Keywords: crush smear cytology; granular cell tumor; immunohistochemistry; neurocytology; pituitary tumor.