Endocrine Abstracts

Our patient presented at the age of 29 years with headaches and galactorrhoea and was found to have a prolactin level of more than 3000 mu/L. Her other pituitary function was normal. MRI pituitary showed 2×2 cm lesion with suprasellar extension and some distortion of the optic chiasm. She was started on Cabergoline 0.5 mg twice weekly for a presumed macroprolactinoma. Visual testing was normal. The repeat MRI four months after initiation of dopamine agonist therapy showed significant reduction in size of the macroprolactinoma but some cystic changes. Her prolactin level normalized within 4 months. Cabergoline was stopped and bromocriptine 5 mg was started as she was planning a pregnancy. She could not tolerate bromocriptine and was switched back to Cabergoline a few months later. The risks and benefits of remaining on Cabergoline through pregnancy were discussed and she decided to remain on Cabergoline 0.5 mg twice a week. This was stopped at 36 weeks gestation as she wished to breastfeed. 12 days postpartum she developed severe headaches and Cabergoline was re-started on the presumption that her macroprolactinoma had increased in size. Surprisingly, MRI showed that the previous cystic lesion had collapsed down and there was only a very slim crescent of pituitary tissue in the floor of the sella. The prolactin level prior to restarting Cabergoline was normal. Glucagon stimulation testing six weeks later showed normal GH and cortisol responses. She is reviewed regularly in clinic. She has not been on any treatment since 2007 and her prolactin remains normal. Her most recent MRI still shows a partially empty sella. We assume that her macroprolactinoma infarcted during the peri-partum period. It is not uncommon for patients with microprolactinomas to be ‘cured’ by pregnancy but this is the first case we have come across with a macroprolactinoma.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.