Granular tumors of the central nervous system: A case series

ABSTRACT Introduction: Granular cell tumors of the central nervous system are rare tumors. To date, eight cases arising from cranial nerves have been reported. Granular cell tumors have also been found arising from the neurohypophysis and its stalk. Due to their rarity and histological similarity to other central nervous system (CNS) tumors with a granular appearance, they often pose a diagnostic conundrum. The differential diagnosis is surprisingly diverse and includes granular cell astrocytoma, infundibular granular cell tumor, spindle cell oncocytoma of the adenohypophysis, granular and oncocytic variants of pituitary adenoma, meningioma, pituicytoma and intrasellar schwannoma. Distinguishing between the CNS tumors with granular features is important because some tumors have an increased recurrence risk or a poor prognosis. Case Report: To highlight the histological features of granular lesions of the central nervous system, including the immunohistochemical profile and electron microscopic depiction, we review two cases each with a similar granular histology and a different final diagnosis. Conclusion: Thorough online literature search revealed several cases of granular cell lesions of the CNS, however, oftentimes the diagnosis is difficult to come by and the differential is long. Conclusion: Granular cell tumor and its variants, though uncommon, must be included in the differential diagnosis of CNS lesions.