Endoscopic endonasal resection of neurohypophyseal granular cell tumor: a case report and review of 88 published cases

Background: Granular cell tumor (GCT) of the neurohypophysis is a rare tumor originating from the posterior pituitary/infundibulum, classified as WHO grade I. Due to its imaging characteristics being highly similar to those of common sellar lesions, diagnosis typically relies on histopathology and immunohistochemistry. Case presentation: A 43-year-old male presented with a one-month history of pulsatile temporal headaches without significant visual complaints. Endocrine tests showed reduced levels of growth hormone and prolactin. CT scan of the head and MRI of the sellar region revealed a well-defined solid mass in the sellar/suprasellar region (approximately 20×19×21 mm), compressing the optic chiasm and closely associated with the pituitary stalk. The patient underwent endoscopic transnasal transsphenoidal tumor resection. Intraoperatively, the tumor was soft but highly vascular, and adhered to the pituitary stalk, requiring meticulous hemostasis and en bloc removal. Postoperative MRI confirmed total resection. Histologically, the tumor consisted of polygonal to spindle-shaped cells with abundant eosinophilic granules in the cytoplasm. Immunohistochemistry showed positivity for TTF-1, S100, and CD68, with a Ki-67 index of approximately 5%, while SOX10 was negative, supporting the diagnosis of neurohypophyseal GCT. Literature review: We reviewed 88 published case reports to compare demographic characteristics, clinical presentations, endocrine abnormalities, treatment strategies, and recurrence rates. Conclusion: Neurohypophyseal GCT should be included in the differential diagnosis of solid sellar/suprasellar masses associated with the pituitary stalk. Endoscopic transnasal transsphenoidal resection is effective, but the rich vascular supply and adhesion to the pituitary stalk can increase the surgical difficulty. Due to the potential for late recurrence, long-term follow-up is recommended.