College of American Pathologists
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Pathology Report: Endometrial Polyps

Posted April 1, 2005

The uterus is mostly made of muscle but is lined by endometrial tissue that thickens and thins at different phases of the menstrual cycle. Each cycle the endometrium grows and changes to prepare the uterus for pregnancy. The most important hormone causing this growth is estrogen. If a woman does not become pregnant, most of the tissue is shed causing a menstrual period.

Sometimes, areas of the endometrial tissue will grow too much, creating a polyp. Polyps are attached to the wall of the uterus by a stalk and grow outward into the endometrial cavity. Growths can be single or multiple and are generally small, about the size of a pencil eraser or fingertip, but if left untreated can become very large.

Endometrial polyps are common, affecting 10-24% of women. They are commonly seen in women 40-50 years old and are rare after menopause. The exact cause is unclear, but polyps seem to be related to excess estrogen levels. They may also be associated with tamoxifen, a drug used in breast cancer therapy.

Since most polyps are small, they often do not cause symptoms. Women who have polyps may experience heavy menstrual bleeding (menorrhagia) and spotting between periods (metrorrhagia) or after sex. Since these symptoms are also associated with more severe illnesses, such as uterine cancer, it is important for women who experience them to see their doctor. Endometrial polyps are almost always benign. Less than 1% are associated with cancer and risk increases with age.

Diagnosis of polyps can be made on sonohysterogram (an ultrasound done with sterile water in the uterus) or hysteroscopy (a tube with a camera that can be used to look in the uterus), but biopsy or removal of the polyp is the only way to make a definitive diagnosis. Endometrial polyps can be treated with the help of a hysteroscope and targeted removal or with dilation and curettage (D&C), which scrapes off the lining of the uterus.

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NewsPath® Editor: Megan J. DiFurio, MD, FCAP
This newsletter is produced in cooperation with the College of American Pathologists Public Affairs Committee and may be reproduced in whole or in part as a service to the medical community. Copyright © 2006 by the College of American Pathologists.
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