Intrasellar gangliocytomas associated with acromegaly.

The present study was designed to investigate the immunohistochemical characteristics of gangliocytomas associated with growth hormone (GH)-secreting pituitary adenomas. In our surgical collection of 476 GH-secreting adenoma cases, we examined tumor tissue from 6 patients (1.3%). All 6 patients were women, ranging from 29 to 52 years (mean, 40.3 +/- 9.5 SD) of age. Among 470 patients with GH-secreting adenomas without gangliocytoma, there were 255 female and 215 male patients. The preponderance of female patients with gangliocytomas was striking. Histological examination of the resected specimens showed areas of ganglion cells and adenomatous cells. Ganglion cell lesions were stained positively for synaptophysin (4 of 4; 100%) and neurofilament (4 of 4; 100%) as well as GH-releasing hormone (5 of 6; 83.3%). Subtypes of GH cell adenomas included 4 cases of sparsely granulated type and 2 cases of mixed GH and prolactin (PRL) cell adenomas. Based on these findings, we hypothesized that the intrasellar gangliocytoma promoted the growth of the pituitary adenoma by chronic overstimulation from excess GH-releasing hormone.