Endocrine Abstracts

Elevated macroprolactin level is one of the reason of misdiagnosis and mismanagement of hyperprolactinamia. About 10% of population have incidentalomas and it also can combine with increasing of prolactin (Prl).

Three hundred and thirty patients with hyperprolactinemia (Prl>600 mU/l) were studied: 192 women and 138 men in age of 30 (25; 39) and 35 (29;46) years respectively. Clinical, biochemical and MRI methods were used. Prl, LH, FSH and Testosterone levels were determined by fluorescence method. Monomeric Prl (monPrl) was determined after polyethylene glycol precipitation (Delfia; Finland): a recovery of <40% was accepted as macroprolactinaemia.

Macroprolactinemia was identified in 64 patients (19.4%): 51 women (26%) and 13 men (9.4%). True hyperprolactinaemia was founded 266 patients (80.6%). Median of Prl level in group with macroprolactinemia was 1080 (922; 1324) mU/l in women and 1004 (698; 1600) mU/l in men; monPrl level was – 271 (222; 331) mU/l and 251 (182; 444) mU/l respectively.

Pituitary adenomas were revealed in 195 (59.1%) patients. Only 17 of them (8.7%) had macroprolactinemia: 12 with microadenomas (7 women and 5 men) and 5 with macroadenomas (1 woman and 4 men). Median of Prl level in this group was 1055 (947; 1509) mU/l in women and 1253 (887; 1770) mU/l in men; monPrl – 248 (193; 302) mU/l and 265 (182; 444) mU/l respectively.

Clinical features of hyperprolactinemia were in 9 men and in 2 women with macroprolactinemia and pituitary adenomas. All of them had increased monPrl level. Cabergoline treatment was prescribed for these patients. There were no clinical symptoms in other patients.

This investigation revealed that macroprolactinaemia in patients with pituitary adenomas is found out rare than in patients with hyperprolactinemia in whole. Reasonability of medical treatment of these patients should be determined on monPrl level, not only on Prl level.