J. Endocrinol.lnvest. 18:436-441,1995 Prolactinoma in 53 men: Clinical characteristics and modes of treatment (male prolactinoma) M. Berezin*, I. Shimon*, and M. Hadani** *Institute of Endocrinology and **Departement of Neurosurgery, Sheba Medical Center, Tel Hashomer, Israel ABSTRACT. The data of 53 men treated for hy- perprolactinemia were reviewed retrospectively to determine the efficacy of the medical and surgical treatment. The clinical assessment, radiological and neuro-ophthalmological investigations and hor- monal measurements were performed before treat- ment as well as during the follow-up period. Imaging evaluation included computed tomography andlor nuclear magnetic resonance of the pituitary. The hormonal profile examined was PRl, FSH, lH and testosterone, as well as TSH, T4, T3 and cor- tisol. Thirty patients were treated solely by dopamine agonists (DA), twenty-two men had pi- tuitary surgery in addition to DA treatment, and one patient was operated with no need for medical treatment. Decreased sexual function was the most frequent presenting symptom (85% of the men). Most of the patients had large invasive macroade- nomas, with suprasellar extension. More than 40% INTRODUCTION Hyperprolactinemia in men is less common than in women. In male hyperprolactinemia large tumors with high prolactin levels usually predominate (1 , 2) while in women, microadenomas with lower hor- mone levels are found (3-5). The clinical features of this syndrome are different in men and women . In the latter the common symptoms are menstrual irregularities, infertility and galactorrhea (3, 4, 6) whereas the major complaints in men are impo- tence and loss of libido (1,2, 7, 8) . A few series of men with prolactinomas have been published (1, 2, 7), many points of pathogenesis, symptomatola- ogyand the preferred therapeutic approach is still questionable. We report our experience with 53 hy- perprolactinemic men and describe the presenting Key-words: Prolactin, pituitary adenoma, men. dopamine antagonists. Correspondence: Dr. Meir Berezin, Institute of Endocrinology, Sheba Medical Center, Tel Hashomer 52621, Israel. Received May 24, 1994; accepted March 28, 1995 436 had visual field defects. Baseline PRl (mean ± SE) was 51,842 ± 9,292 mUll and decreased to a lev- el below 575 mUll in 70% of the patients after DA therapy. Mean testosterone, FSH, and lH levels increased slightly but Significantly from the low baseline values. Complete clinical response to DA was achieved in 49% of the men and the tumor mass disappeared entirely in 21 %, and incom- pletely in 42%. The surgical success rate (trans- sphenoidal or trans-cranial operation) was low - on- ly one of the 23 patients operated recovered com- pletely, and most of the patients were left with hor- monal deficits and hyperprolactinemia. These find- ings indicate that continuous medical treatment with DA should be the preferred mode of treatment for male prolactinomas. Removal of these large tumors is recommended only when the tumors are life- threatening or if drug resistance or severe adverse reactions to DA develop. features, the clinical, radiological and laboratory characteristics, the medical and surgical treatments and other aspects of this syndrome. PATIENTS AND METHODS Between 1974 and 1993, 53 hyperprolactinemic men were diagnosed and followed in the Institute of Endocrinology at the Sheba Medical Center, Tel Hashomer, Israel. A full clinical evaluation was per- formed before any treatment was started, and in- cluded investigation of serum levels of prolactin (PRl), luteneizing hormone (lH), follicle stimulat- ing hormone (FSH) and testosterone, as well as cor- tisol, thyroid-stimulating hormone (TSH), thyroxine and triiodothyronine levels. The blood samples were taken during the morning hours between 07:30 and 09:00. Recurrent hormonal assessments were performed during the follow-up period every three months or less according to the clinical state. In patients with suspected latent insufficiencies in pre- or post treatment periods ( medical or surgi- cal) dynamic tests (TRH , lHRH, ITT, GHRH, CRH)