A Case of Mixed pitNET-Gangliocytoma of the Sella Turcica: Histopathologist's take on Extremely Rare Occurrence

Mixed pituitary neuroendocrine tumors (pitNET)-gangliocytomas are extremely rare sellar region World Health Organisation (WHO) Grade-I tumors. We report the case of a 31-year-old Pakistani male with a presenting complaint of headache and gradual loss of vision for a period of few months. On magnetic resonance imaging (MRI), a sellar/ suprasellar and parasellar mass lesion was identified. A differential of pituitary macroadenoma was considered. The mass was excised and the surgery was uneventful. Histopathology revealed a biphasic tumor composed of small monomorphic nests and solid sheets of pitNET cells (synaptophysin and chromogranin A positive, S100 negative) and large voluminous eosinophilic cells of the gangliocytoma component (synaptophysin, chromogranin A and S100 positive). This case highlights a tumor with features of both neuronal and endocrine neoplasms. Although their presentation resembles that of pitNETs, their treatment response and behavior are more consistent with glioneuronal tumors, resulting in a highly favorable phenotype and treatment response.