A prolactinoma is the most common type of benign brain tumor. This type of tumor is often misdiagnosed. Normally, people don’t experience headaches, but they have other systemic symptoms instead. Some patients have painful lactating breasts that produce milk. Women may also experience changes in their menstrual cycles, such as shorter or delayed periods. Later, people will experience changes in their vision. Patients may present after automobile accidents or clumsiness when struck from the side because they had developed bilateral hemianopsia, where they lost their side vision.
Patients are diagnosed with prolactinoma by having high levels of serum prolactin. They are then confirmed by an MRI showing growth of the anterior pituitary, which sits in the sella turcica of the brain. The sella turcica sits above the optic chiasm, which is compressed, causing visual disturbances.
The anterior pituitary not only produces prolactin, but it also produces five other hormones that can be decreased by the gland’s overproduction of prolactin. These other hormones are luteinizing hormone (LH) and follicle stimulating hormone (FSH), which produce progesterone and estrogen in women and testosterone, Muller’s inhibitory factor (MIF) and protein of androgen binding (ABP) in men. Adrenocorticotrophic hormone (ACTH) is also produced, causing the adrenal gland to release cortisol. Thyroid-stimulating hormone (TSH) comes from the anterior pituitary gland, which causes the thyroid hormones T3 and T4 to be released from the thyroid gland. Growth hormone (GH) is also produced which acts on all cells in the body for growth and repair and stimulates the release of insulin-like growth factor (IGF) from the liver to help maintain levels of body blood glucose. If prolactinoma is left untreated, the anterior pituitary will not produce enough of these hormones to affect other organs in the body to function properly, and patients will experience symptoms of decreased sexual functioning, Cushing’s syndrome, hypothyroidism and hyperglycemia.
There are several treatment options for a prolactinoma. The first treatment option is medication. The best medical option is bromocriptine. This is an older drug that has been used for many years, but it has several side effects, such as chest pain, confusion, and hypoglycemia, which some patients cannot tolerate. So, the alternative drug that can be prescribed instead is carbergoline. These drugs are dopamine agonists that work to reduce the amount of prolactin produced by the anterior pituitary gland in the brain. The ultimate treatment for a prolactinoma is surgery. The procedure is the surgical removal of the brain tumor through the patient’s nose.
The prognosis of a prolactinoma is very good. Ninety-five percent of patients with this benign tumor live a functional life with few side effects. If the tumor is small, women will still be able to get pregnant and have children. Since prolactin opposes the release of estrogen from the ovaries, women have an increased risk of getting osteoporosis. Patients should therefore be followed by their treating physician and/or a neurologist to monitor the growth of the prolactinoma. Fortunately, prolactinomas do not grow much after five years and patients can determine their long-term treatments at this time.
So if you experience any changes in your menstrual cycle, vision, health, and/or behavior, see your doctor and ask, “Do I have a prolactinoma?” »
