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

Abstract

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.

Granular cell tumor of the neurohypophysis presenting as a third ventricle mass

“…GCT, which may also present with a suprasellar location, 17 can in rare circumstances radiologically mimic chordoid glioma, which arises within the third ventricle 21 ; moreover, GCT can simulate low-grade gliomas at intraoperative frozen sections and cytologic smears. 22 Chordoid glioma is a rare WHO grade 2 glial neoplasm that arises in the anterior third ventricle, clinically causing hydrocephalus and histologically presenting with a wide spectrum of histological architectures, ranging from the prototypical chordoid one to a diffuse growth pattern, frequently accompanied by a stromal lymphocytic infiltrate. 1,23 Chordoid glioma strongly expresses GFAP, TTF1, Vimentin, EMA, and CD34.…”

“…While histomorphology was indeed characteristic of a granular cell neoplasm, 20 the peculiar radiological presentation prompted an immunohistochemical and molecular workup that included markers for chordoid glioma, which can present with a wide morphological spectrum, and for granular cell glioma/glioblastoma, which harbors a completely different biological behavior and, therefore, needs to be excluded. GCT, which may also present with a suprasellar location, 17 can in rare circumstances radiologically mimic chordoid glioma, which arises within the third ventricle 21 ; moreover, GCT can simulate low‐grade gliomas at intraoperative frozen sections and cytologic smears 22 …”