Endocrine Abstracts

Gangliocytomas are uncommon neuronal tumors that can sometimes cause endocrine syndromes. A few such cases have been reported in association with Cushing’s disease. In most instances, the tumor contained CRH and was associated with pituitary corticotroph hyperplasia or adenoma (mixed lesion). Only one case of isolated gangliocytoma causing Cushing’s disease per se has been described.

We report the case of a 62 year-old woman whose clinical picture and endocrine testing clearly demonstrated ACTH-dependent Cushing’s syndrome. Pituitary MRI showed a 12 mm homogeneous, T2-weighed hyperintense, infrasellar mass with delayed contrast enhancement. The mass was bulging into the sphenoidal sinus with scalloping of the clivus. Transsphenoidal surgery was performed and allowed complete resection of the tumor with sparing of the whole normal anterior pituitary. Very low postoperative serum cortisol and ACTH levels were observed, both in the early postoperative period and one month later, proving that the resected lesion was entirely responsible for the clinical picture. Pathology and immunohistochemistry demonstrated a benign tumor composed of mature neuronal cells most likely arising from the posterior pituitary, resembling hypothalamic ganglion cells and expressing ACTH. The gangliocytoma was surrounded by a rim of pituitary tissue containing some ACTH-producing endocrine cells. Careful analysis of the resected lesion did not reveal any pituitary microadenoma. CRH immunostaining of the tissue is currently being performed in order to determine whether the gangliocytoma was also responsible for an associated CRH-induced corticotroph hyperplasia.

This infrasellar ACTH-containing gangliocytoma singles out the few reported cases of gangliocytomas causing Cushing’s disease by CRH-induced corticotroph hyperplasia or adenoma. Further analyses on the resected tissue will hopefully allow us to better describe the case of our patient and contribute to the understanding of this rare entity.