Mixed gangliocytoma/pituitary adenoma: a clinicopathologic study of four cases and review of literature

Purpose To investigate the pathogenesis, clinicopathological characteristics, diagnosis and differential diagnosis of the mixed gangliocytoma/pituitary adenoma (MGPA). Methods Four cases of MGPA were studied with HE and immunohistochemical EnVision-plus staining. Results All patients were female, with age ranged from 10 to 35 years (mean 26.5 years). Clinically, three cases were endocrinologically symptomatic and one case was falling sickness. Histopathologically, two distinct neoplastic cell populations were observed in the same tumor mass. The first population was composed of many ganglionic cells showing large nuclei, prominent nucleoli, and Nissl bodies, which were positive for CgA, Syn, S-100 protein and negative for GFAP. The second population was similar cells in sizes and shapes, with round-oval nuclei, abundant and acidophilic or pale cytoplasm, which were immunoreactive for GH and PRL. Conclusions MGPA is a very rare mixed pituitary tumor with good prognosis. It arises mostly on young woman presenting with acromegaly. The diagnosis depends mainly on HE as well as immunohistochemical staining.