GANGLIOGLIOMA OF THE NEUROHYPOPHYSIS WITH SECRETION OF VASOPRESSIN

A patient with a ganglioglioma of the neurohypophysis developed the sy ndrome of inappropriate antidiuretic hormone secretion (SIADH). We pre sent the case and describe its microscopic and ultrastructural feature s. Malignant neoplasms were thought to be the main cause of ectopic pr oduction of vasopressin. Head trauma, infection, or drugs, however, ca n also induce hypersecretion of vasopressin. Mechanical compression of the pituitary stalk can lead to an excessive antidiuretic hormone (AD H) release by affecting the inhibitory system. Primary neuroendocrine tumors of the hypothalamic-neurohypophyseal system are extremely rare. We demonstrate the presence of vasopressin in the tumor cells by immu nocytochemistry. This represents the first case of SIADH caused by a t umor of the neurohypophysis.