May 2008 case 1 - 59-year-old male with panhypopitutism 59-year-old male with panhypopitutism - Diagnosis - Discussion

A 59 year old male teacher developed symptoms of panhypopituitarism. MRI revealed a solid homogeneously enhancing mass in the sella measuring 1.8 cm extending into the suprasellar cistern causing mild compression of the optic chiasm. The resected specimen consisted of a fascicular and storiform arrangement of elongated cells with abundant eosinophilic cytoplasm lacking granularity. No mitotic figures were seen. Immunohistochemical studies for chromogranin and pituitary hormones were negative. The lesional cells expressed GFAP, PGP9.5, and S100. Electron microscopy showed lesional cells bearing abundant intermediate filaments and rare neurosecretory granules. The final diagnosis was pituicytoma. Pituicytomas are rare primary tumors of the neurohypophysis. The putative cell of origin is the pituicyte, which is a glial cell normally residing in the posterior pituitary and pituitary stalk, the function of which is thought to be the regulation of hormone secretion from the neurohypophysis. The natural history of the pituicytoma is not well understood due to their rarity, although the largest case series in recent years suggests that complete resection may be curative. However, there is a chance of recurrence following sub-total resection with the role of adjuvant therapies being uncertain at this time.