Successful treatment of a large macroprolactinoma with cabergoline during pregnancy

We report a pregnant woman with a large macroprolactinoma successfully treated with cabergoline after a suboptimal response to bromocriptine. A 7 week pregnant woman with a history of a prolactinoma presented to the endocrine clinic with the complaints of headaches and nausea. She had a prolactin level of 65 microg/L 1 1/2 weeks following her last menstrual period. Bromocriptine was discontinued at 6 weeks gestation when pregnancy was confirmed. A PRL concentration was 1899 microg/L (non-pregnant normal range 1.39-24.20 microg/L, the mean peak levels during pregnancy reported from the literature are 200-210 microg/L) at 7 weeks gestation, and a repeat was 2197 microg/L. An MRI showed a 3 x 2.2 x 2.5 cm seller mass abutting the optic chiasm and displacing the optic nerves superiorly; the visual field testing was normal. Bromocriptine was reinitiated and the patient responded initially with decreasing headaches and declining PRL concentrations to 1488 microg/L at 15 weeks gestation. However, PRL increased to 1836 microg/L at 16 weeks and remained elevated despite bromocriptine 2.5 mg three times a day; in addition, she complained of severe nausea, vomiting, and persistent headaches. Cabergoline was added at 18 weeks gestation. PRL decreased dramatically from 1710 to 859 microg/L in 1 week, and to 488 microg/L within 4 weeks. A repeat MRI showed more than 30% reduction in tumor size. Bromocriptine was discontinued at 24 weeks gestation; she was maintained on cabergoline 0.5 mg twice a week without complaints. PRL levels ranged from 190 to 278 microg/L during the last 10 weeks of pregnancy. She had a C-section electively at 37 weeks gestation and delivered a healthy baby. Management options in this patient and during pregnancy are discussed.