A 51-year-old house woman visited the Department of Neurosurgery, Osaka University Hospital for examination of the head injury on Oct. 7, 1975. Neurological examination was normal. Endocrinological examination showed galactorrhea. The patient had a past history of premature menopause. Plain skull films revealed enlargement of sella turcica and CT scan showed sellar tumor with suprasellar expansion which was enhanced by contrast medium. The serum prolactin (PRL) level was 3,290 ng/ml. Diagnosis of PRL secreting pituitary adenoma (prolactinoma) was made. Though surgical removal of the tumor was recommended, it was refused by the patient. Therefore, careful observation was continued as an out-patient until May 1979 when she noticed a temporal hemianopsia of her left eye. She was admitted and had partial removal of the tumor via frontal route and subsequent irradiation (total dose of 5,000 rad by Lineac). The tumor was verified to be a prolactinoma by the immunohistochemical staining. Postoperative course was uneventful and she lead a normal life. In Oct. 1981, severe faceache began and she was readmitted. Sella was destructed extensively and CT scan revealed a hugh sellar tumor with multi-directional extrasellar extension which was less enhanced than that of the first study. The serum PRL level was 588 ng/ml and the regrowth of prolactinoma was suspected. High dose bromocriptine (40 mg/day) therapy was started. The serum PRL level rapidly fell to the negligible value, however, shrinkage of the tumor was not observed. On Jan. 20, 1982, suddenly she developed a left hemiparesis and her level of consciousness gradually deteriorated. On Mar. 11, 1982, the second operation was performed and a solid firm tumor in the base of the skull was partially removed. The tumor was histologically verified to be a fibrosarcoma. After the second operation bromocriptine therapy was discontinued, however expected elevation of the serum PRL level was not recognized. She died on Apr. 4, 1982.