Supra-sellar granular cell tumor: Report of a case with literature review

Abstract

Introduction and importance: Granular cell tumor (GCT) originating from the sellar and suprasellar regions, specifically from the neurohypophysis, is a rare neoplasm. Distinguishing GCT from other pituitary tumors, including pituitary adenoma, pituicytoma, and spindle cell oncocytoma, poses significant challenges. Here, we present a rare case of GCT originating from the posterior pituitary in the supra-sellar region.

Case presentation: A 41-year-old woman, with no past medical history, presented to neurology department with decreased visual acuity and peripheral facial paralysis since 3 months. The MRI showed a well-defined supra-sellar, retrochiasmatic, oblong, hypothalamic expansive process. It was isointense T1-weighted, discretely hypotensive T2-weighted, measuring 19x17x16 mm, suggesting pituicytoma or craniopharyngioma. An endoscopic transsphenoidal surgical resection was performed. Microscopic examination showed a proliferation of diffuse architecture made up of rounded polyhedral cells with granular eosinophilic cytoplasm. On immunohistochemistry, tumor cells expressed diffusely TTF1, S-100 protein and SOX-10 confirming the diagnosis of supra-sellar GCT.

Discussion and conclusion: GCTs are rare neoplasms that predominantly exhibit benign behavior, while the malignancy rate remains at 2 %. Histopathology serves as the definitive diagnostic approach for GCTs. These tumors are resistant to radiotherapy and chemotherapy, necessitating surgical resection as the primary treatment modality. Due to the potential absence of distinct tumor masses and local tissue infiltration by tumor cells, complete excision is crucial, with resection extent extending beyond areas of infiltration.

Keywords: Granular cell tumor; Magnetic resonance imaging findings; Neurohypophysis; Pathology; Thyroid transcription factor 1.

Fig. 1

An expansile well-defined oval process was observed above the sella turcica, with isointense signals on both T1 and T2 imaging. There was an anhancement after gadolinium injection.

Fig. 2

H&E (A × 40, B × 200, C × 400 magnification). Microscopic examination showed a proliferation of diffuse architecture made up of rounded polyhedral cells with granular eosinophilic cytoplasm. Nuclei were eccentric, small and regular, without cellular atypia or mitotic figures.

Fig. 3

Immunohistochemical positive stain for TTF-1 (A, ×400), negative stain for chromogranin (B, ×400) and synaptophysin (C, ×400).