Lymphocytic hypophysitis is a rare condition reported to occur only in women. A patient with amenorrhea and hyperprolactinemia was thought to have a pituitary microadenoma but was subsequently found to have lymphocytic hypophysitis and pituitary-specific autoantibodies. Photomicrographs taken upon transsphenoidal surgical exploration revealed the lymphohistiocytic infiltrate of the pituitary. The pituitary reserve was tested. Autoimmune hypophysitis should be included in the differential diagnosis of amenorrhea and galactorrhea.