Lymphoid adenohypophysitis is an autoimmune disorder. Eighteen percent of the multipartums are reported to have autoantibodies to pituitary tissues. The symptoms in lymphoid adenohypophysitis, such as hypopituitarism and sellar tumors, exhibit spontaneous remission. The pituitary is a feasible target organ in other autoimmune diseases of the endocrine system. Of these patients, 19/287 showed a positive immune reaction with pituitary tissue antigens. Our three female patients with sellar and suprasellar mass were clinically diagnosed as having lymphoid adenohypophysitis, because of the spontaneous regression of tumors, or presence of immunologically and endocrinologically abnormal findings. The first case was a 31-year-old woman who had amenorrhea and galactorrhea syndrome for two years after delivery of her second child. CT scan revealed a supraseller enhanced mass lesion. She had concomitant signs of recurrent meningeal irritations. The number of cells in the CSF increased, though the protein concentration increased only slightly. During a one-year close observation, the suprasellar mass spontaneously regressed. The second patient was a 66-year-old woman. In 1945, she underwent hysterectomy and oophorectomy for appendicitis followed by adnexitis. She was admitted because of episodes of headache, vomiting and visual field defect in 1983. CT scan also showed a contrast enhanced mass in the suprasellar region. She had two episodes of high fever. After the treatment with antibiotics and anti-inflammatory agents for 4 months, the tumor disappeared. The third case was a 20-year-old female. She had neither neurological nor endocrinological abnormality, except for attacks of vertigo, nausea and vomiting.(ABSTRACT TRUNCATED AT 250 WORDS)