Isolated adrenocorticotropic hormone deficiency due to probable lymphocytic hypophysitis in a man.

We report a male patient who presented with severe fasting hypoglycemia in which extensive pituitary and adrenal investigations were diagnostic of isolated ACTH deficiency of pituitary origin. The finding of autoimmune subclinical primary hypothyroidism strongly suggested an autoimmune etiology of the pituitary disease. Lymphocytic hypophysitis, although very rare in male patients, has to be kept in mind when studying patients with pituitary failure of unknown origin, especially when other autoimmune endocrinopathy is present.