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I am an Internal Medicine Resident in Rio de Janeiro, Brazil. I have seen a 23 year old woman which has a history of galactorrhea started 5 years ago. Her prolactin at that time was around 50 ng/ml and a pituitary MRI showed a 5mm adenoma. She had normal menses and no other symptoms. Her gynecologist diagnosed a microprolactinoma and started her on Bromocriptine SRO 2.5mg but the galactorrhea only improved with 5mg od. She was followed during all these years with annual MRI and prolactine levels and the tumor never grew or shrunk (always the same 5mm) and her prolactin never had great variations (mean=50 ng/ml, minimum = 35ng/ml, maximum = 55ng/ml), despite the use of medication or not. She also has severe side effects with Bromocriptine and now stopped the medication, with recurrence of her symptoms. My questions about this case are: do you think this patient really has a microprolactinoma or could she have a normoprolactinemic galactorrhea (maybe with macroprolactinemia) associated with a pituitary incidentaloma? The other question is that we are planning to start her on Cabergoline and which dose you think will control her symptom and would you start her on?
Thank you very much,
Luiza Fuoco, MD
Response
Regarding your clinical case, the presence of galactorrhea without menses disturbances may be related either to mild hyperprolactinemia or to normoprolactinemic galactorrhea, a non rare event mainly in women that already delivered and nursed a baby. Therefore, this young lady may harbor either a microprolactinoma or a pituitary incidentaloma associated with macroprolactinemia. The fact that she never attained normal serum prolactin levels on bromocriptine points to partial resistance to the dopamine agonist or irregular drug intake. Individuals with macroprolactinemia usually normalize serum prolactin during dopamine agonists therapy, even though, due to prolonged half-life, it may require and extra time to reach normal values. Practical point: is the galactorrhea bothersome? If not, and if the patient has normal ovulatory menses, no treatment is needed. If it is inconvenient, screen for macroprolactinemia and try cabergoline ( 0.5mg) twice a week with food), aiming at better tolerance and effectiveness.
Sincerely,
Marcello D. Bronstein, MD