What is an endometrial polyp?
An endometrial polyp is a growth found within the uterine cavity. It is different from a uterine fibroid (leiomyoma). Fibroids originate from the uterine musculature and therefore can occur in any part of the uterus—inside (submucous), outside (subserous) or in the wall (intramural). Polyps originate from the lining of the uterus itself. Since the lining of the uterus is within the cavity –also known as the endometrial cavity—polyps are always located in the interior of the uterus. Polyps vary in size—from millimeters to centimeters—can be single or multiple, and typically occur at the top-most portion of the uterus.
The important thing to remember about polyps is that they’re composed endometrial (or lining) cells. Unlike fibroids which have almost a zero potential for malignancy, polyps have a small likelihood of being malignant—around 3%.
What are the symptoms of endometrial polyps?
Polyps are often associated with abnormal uterine bleeding. They can cause bleeding in between periods (intermenstrual bleeding or spotting), irregular periods (metorrhagia), post-coital bleeding (bleeding following intercourse) and post-menopausal bleeding. Occasionally endometrial polyps can also cause severe cramping during menses (dysmenorrhea).
Key points to know about endometrial polyps
- Nobody knows the exact incidence of endometrial polyps. The reason for this is simple—many women who had polyps don’t have symptoms from them. In Scandinavia where ultrasounds are performed as a routine part of annual examination they are commonly found in women who do not have symptoms.
- Endometrial polyps are found in up to 39% of women with abnormal pre-menopausal bleeding and 21-28% of women with post-menopausal bleeding.
- Most endometrial polyps are benign but between 2-4% of them are pre-malignant or malignant.
- Polyps are often suspected on a transvaginal ultrasound. But….
- The only specific way to know if you have a polyp or another issue—such as a fibroid or thickened endometrial (lining) tissue–within the uterine cavity is to remove it and send it to the pathologist. Tests such as ultrasounds, sonohysterograms (also called hysterosonograms) cannot absolutely diagnose polyps.
- Polyps are best diagnosed by looking at them with a hysteroscope—a technique known as diagnostic hysteroscopy. Here are some examples of endometrial or uterine polyps. But to absolutely make the diagnosis of a polyp it requires removal and examination by a pathologist.
- The risk factors for endometrial polyps include, increasing age, obesity, hypertension, hormone replacement therapy and a breast cancer medication called tamoxifen.
Treating endometrial polyps
Despite the fact that endometrial polyps are common there is a great deal that is not known in terms of their management. Here are some common issues that physicians should address if they’re treating you for endometrial polyps.
- Endometrial polyps tend to reoccur–estimates on recurrence vary from 15-43%. If they are removed one needs to address this issue and do what is possible and practical so that they don’t come back.
- For many women with heavy menstrual bleeding—as well as an endometrial polyp—removing the polyp alone will not necessarily improve their heavy flow. About 50% of women who have polyps removed because of symptoms of abnormal periods eventually require other interventions. For this reason it is important to deal with polyps in a comprehensive way.
- As noted above, pre-cancerous or cancerous changes occur in 2-4% of women with endometrial polyps. In about 1/3 of cases the changes occur at the base of the polyp—therefore the focus must be to get the entire polyp out.
- Younger women, who wish to preserve their fertility, need to have as much of the polyp removed as possible—without damaging the surrounding endometrium.
- After polypectomy (removal of the polyp) physicians should institute a program of monitoring endometrial polyps to be certain that they do not recur.
How likely are polyps to reoccur?
A variety studies estimate the risk of recurrence of endometrial polyps in pre-menopausal women to vary from 15-43%. The rate of recurrence in post-menopausal women is less well known.
How are endometrial polyps removed?
There are many techniques for removing endometrial polyps—by far the best is using the resectoscope. The resectoscope is an instrument that allows us to look directly into the uterine cavity and operate at the same time. At the tip of the resectoscope is a wire loop that allows us to cut away endometrial polyps, remove them and send them for analysis.
What can be done to reduce the likelihood of polyp recurrence?
There appear to be 2 proven ways to reduce the likelihood of polyp recurrence—the insertion of a Mirena IUD and endomyometrial resection (EMR). The Mirena IUD is an excellent choice for women who wish to preserve their childbearing options. Endomyometrial resection may be a preferred method of preventing recurrence in selected women with endometrial polyps. It is also possible to perform a partial endomyometrial resection in appropriate candidates.
The resectoscope is the main instrument used for removing endometrial polyps—it’s very, very versatile. An advantage of the resectoscope is that it can be used for other things as well—removing fibroids, the base of the polyp and even uterine lining tissue.
Endometrial polyps are a common cause of abnormal uterine bleeding in women of all ages. Care must be taken to remove them in their entirety in order to obtain and adequate specimen for analysis and address the issue of their recurrence. Additionally, for women with menstrual disorders (who have completed childbearing) it may be necessary to address other causes of abnormal menstrual bleeding since many women who undergo polypectomy later discover that they may require additional procedures to comprehensively address their menstrual problem.