n engl j med

349;21

www.nejm.org november

20, 2003

The

new england journal

of

medicine

2035

clinical practice

This

Journal

feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines,

when they exist. The article ends with the authors clinical recommendations.

Prolactinoma

Janet A. Schlechte, M.D.

From the Department of Internal Medicine,University of Iowa, Iowa City. Address re-print requests to Dr. Schlechte at the De-partment of Internal Medicine, 157 MRF,University of Iowa Hospitals and Clinics,200 Hawkins Dr., Iowa City, IA 52242, or atjanet-schlechte@uiowa.edu.

N Engl J Med 2003;349:2035-41.

Copyright 2003 Massachusetts Medical Society.

A 22-year-old woman who wants to become pregnant has had no menses since shediscontinued the use of an oral contraceptive one year ago, and recently, galactorrheadeveloped. She takes no medications and has had no headaches, visual loss, dyspareu-nia, or decreased libido. Physical examination shows no abnormalities, except for thebilateral breast discharge. A test for serum human chorionic gonadotropin is nega-tive, the thyrotropin level is normal, and the serum prolactin level is 95 g per liter.Magnetic resonance imaging (MRI) reveals a mass, 3 mm in diameter, in the anteriorlobe of the pituitary. How should she be treated?

Prolactin-secreting tumors are benign neoplasms that account for about 40 percent ofall pituitary tumors. Over 90 percent are small, intrasellar tumors that rarely increase insize.

1-4

The primary action of prolactin is to stimulate lactation, but it is the effect ofprolactin on gonadal function that warrants clinical attention. Hypersecretion of pro-lactin leads to infertility and gonadal dysfunction by interrupting secretion of gonado-tropin-releasing hormone, inhibiting the release of luteinizing hormone and follicle-stimulating hormone, and impairing gonadal steroidogenesis.

5,6

clinical presentation

The most common symptoms of hyperprolactinemia in premenopausal women areamenorrhea and infertility. Galactorrhea occurs in about 80 percent of such women,and some women with prolactinomas have infrequent menstrual flow (oligomenor-rhea) or regular menses.

1

Hyperprolactinemia is often detected after discontinuationof the use of an oral contraceptive, but there is no apparent relation between the use oforal contraceptives and the formation of prolactinomas.

7

The majority of prolactinomasin women are small at the time of diagnosis, and headaches and neurologic deficits arerare.

1

In contrast, prolactinomas in men typically tend to be large at the time of diagno-sis and may cause cranial-nerve dysfunction, visual loss, and hypopituitarism.

8

In men,hyperprolactinemia leads to impotence, infertility, and decreased libido, but these arerarely the initial symptoms; galactorrhea and gynecomastia are uncommon.

8

In bothsexes, long-standing hyperprolactinemia leads to low bone density in the spine.

9-11

After prolactin has returned to the normal range, bone density will increase but doesnot reach normal values.

9-11

causes of hyperprolactinemia

The secretion and release of prolactin are mediated by dopamine, and any process thatdisrupts dopamine secretion or interferes with the delivery of dopamine to the portalvessels may cause hyperprolactinemia. Normal prolactin levels in women and men arebelow 25 g per liter and 20 g per liter, respectively. There is a 10-fold increase in pro-

the clinical problem

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