Assessing and Treating Prolactinoma

My girlfriend was diagnosed with a prolactinoma a year ago but was not given any treatment. The endocrinologist just recommended a yearly MRI to track its progression. In the past six months she has been complaining of headaches and visual disturbances. I have a few questions. First, will Bromocriptine, if prescribed, make a difference in her symptoms (galactorrhea, visual disturbances, headaches, loss of libido)? Second, is the surgery, if prescribed, routine? And most of all, will she be able to bear children? S.G.

Prolactin is a hormone produced in both males and females by the pituitary gland. Its major role is to stimulate milk production for the lactating (breastfeeding) female. Other roles for this hormone are less clear. Various factors can cause an increase in prolactin levels, including medications, stress and even breast examinations.

A prolactinoma is a tumor of the pituitary gland that produces an excess of prolactin. The most common prolactin-producing tumor is the microadenoma, which is quite small. The resulting side effects -- such as inappropriate milk production (galactorrhea) and loss of libido -- are due to elevation of blood prolactin levels, not to the presence of the tumor itself. Larger tumors (over about one centimeter) are called macroadenomas and are quite rare. These larger tumors are benign (noncancerous), but their presence can cause headache and visual disturbances. We all get concerned when we hear the word "tumor," and it is scary to think there is a tumor at the base of the brain. But let me reassure you: Pituitary tumors are found in up to 7 percent of autopsies performed on people dying in accidents, so this condition is not all that rare. Frequently an abnormal prolactin elevation is detected as part of a infertility evaluation or in women with decreased libido or irregular menses. In males, impotence is the most common symptom that leads to the identification of high prolactin levels.

Once blood tests detect a prolactin elevation, a magnetic resonance imaging study (MRI) can be performed to look for a tumor. Most tumors, even the large ones, regress when treated with medical therapy. Surgery is reserved for the rare case that does not respond to medication. Pregnancy rates and outcomes are excellent once the prolactin level is normalized. For women without symptoms, many physicians opt to avoid treatment altogether; annual MRIs allow the physician to monitor the tumor and initiate treatment if enlargement is evident.