A 34-year-old woman comes to the physician after several months of amenorrhea. Several home pregnancy tests have been negative. Her past medical history is insignificant. She is married with 2 children and has no plans to have more. Her body mass index is 23 kg/m². Physical examination is unremarkable. Serum prolactin level is 500 ng/mL (normal 5-20 ng/mL). Magnetic resonance imaging of the head shows a 5-mm pituitary mass. This patient is at high risk of developing which of the following if left untreated?

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Explanation: 11ec2b69_bec2_2eb1_8f63_099eed493b97_MD0005_00 This patient has a symptomatic prolactinoma with secondary amenorrhea and a very high prolactin level. Prolactinomas are a relatively common cause of amenorrhea, infertility, and galactorrhea in women. Elevated prolactin levels suppress gonadotropin-releasing hormone, luteinizing hormone, and estradiol, leading to symptoms of hypogonadism including hot flashes, vaginal dryness, and potentially osteoporosis if left untreated. Male patients can develop symptoms of hypogonadism and gynecomastia. Large adenomas may also cause headaches and compression of the optic chiasm, leading to visual field defects (bitemporal hemianopsia). The diagnosis of prolactinoma is strongly suggested by a prolactin level >200 ng/mL (normal 5-20 ng/mL). Mild elevations (20-200 ng/mL) may also be due to a prolactinoma, but other causes such as medications (eg, certain antipsychotics), nipple stimulation, pregnancy, hypothyroidism, and stress should also be considered. If prolactinoma is suspected, magnetic resonance imaging of the pituitary can confirm the diagnosis. In most cases, hyperprolactinemia will respond to treatment with dopamine agonists (eg, cabergoline, bromocriptine), which decrease both the size and prolactin secretion of the adenoma. Surgical intervention can be considered in patients who fail to improve with dopamine agonist therapy, especially if they have significant neurologic symptoms. (Choice A) Prolactin receptors have been identified in coronary artery plaques, suggesting that prolactin may have some effect on the behavior of coronary atherosclerosis. However, studies have not found an association between prolactinoma and incidence of coronary disease. (Choice C) Dopamine agonists, which were initially developed for treatment of Parkinson's disease, suppress production of prolactin and are first-line treatment for prolactinomas. Otherwise, there is no association between prolactinomas and Parkinson's disease. (Choice D) Large pituitary adenomas may induce a mass effect on surrounding structures in the brain, leading to neurologic symptoms. Primary adenocarcinoma of the pituitary, however, is extremely rare. (Choice E) Polycystic ovarian syndrome (PCOS) is a common cause of infertility in women. There are a few case reports of prolactinoma associated with PCOS, and anecdotal evidence suggests it may be causative. However, PCOS is not a common manifestation of prolactinoma. Educational objective: Prolactinoma is a common cause of amenorrhea and infertility in women. Other endocrine effects include galactorrhea in women, gynecomastia in men, and symptoms of hypogonadism in both sexes. Long-term suppression of sex hormone production by prolactinoma in women can lead to osteoporosis. The primary treatment of prolactinoma is dopamine agonists such as cabergoline, which inhibit prolactin secretion and cause regression of tumor size. References: Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/21296991) 2012 update in the treatment of prolactinomas. (http://www.ncbi.nlm.nih.gov/pubmed/22503806)

A 34-Year-Old Woman Comes to the Physician After Several Months