Hypothalamic insufficiency: the cause of hypopituitarism in sarcoidosis.

Ten patients with generalized sarcoidosis and hypopituitarism were studied. Six of these 10 patients presented with sarcoid involvement of the optic nerves resulting in asymmetric visual field defects. All patients had deficiencies of two or more anterior pituitary hormones and seven had abnormalities of water metabolism. Despite hypopituitarism, nine patients had a pituitary responsive to the synthetic hypothalamic releasing factors, thyrotropin releasing hormone and gonadotropin releasing hormone, and the tenth patient had a partially responsive pituitary. The demonstration of pituitary responsiveness allows us to infer hypothalamic insufficiency as the major cause for hypopituitarism in these patients. The combination of visual field defects and hypopituitarism in sarcoidosis is a medically treatable condition that simulates the clinical presentation of a pituitary tumor.