Endometrial Polyps

An endometrial polyp or uterine polyp is an abnormal growth containing glands, stroma and blood vessels projecting from the lining of the uterus (endometrium) that occupies spaces small or large enough to fill the uterine cavity. Endometrial polyps are the most frequently observed pathological finding in the uterus and are usually benign lesions.

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. Endometrial polyps tend to reoccur; rate of recurrence is about 15-43%.

Morphology

An endometrial polyp could be pedunculated or sessile. Gross morphological appearance is smooth, spherical or cylindrical in structure and is tan to yellow in color. The endometrium varies from normal cycling endometrium to simple or complex hyperplasia in the presence of endometrial polyps, and rarely endometrial cancer can be found.

Risk factors

The following factors have been associated with endometrial polyps: Obesity and excess weight gain, use of tamoxifen regardless of timing, Lynch syndrome, use of hormone replacement therapy. ^[1]

Aetiology

The pathogenesis and natural history of endometrial polyps are not very clear. However;

• It is thought to represent a hyperplastic response of normal endometrial tissue possibly originating as a localized hyperplasia of the endometrial basalis secondary to unopposed estrogen
• Monoclonal stromal overgrowth with secondary induction of polyclonal benign glands
• Overexpression of endometrial aromatase suggests a role of this enzyme in the pathogenesis
• Associated with tamoxifen therapy (Am J Obstet Gynecol 2011;205:535.e1)
• Late menopause, hormone replacement therapy and obesity increase the risk (Maturitas 2005;50:231)
• In postmenopausal females, the presence of metabolic syndrome is a predictor (Menopause 2016;23:759)

Clinical features

They are often asymptomatic.  When symptoms occur, symptoms include irregular menstrual bleeding, intermenstrual bleeding, menorrhagia, and postmenopausal bleeding. Bleeding from the blood vessels of the polyp contributes to an increase of blood loss during menstruation and blood “spotting” between menstrual periods, or after menopause. ^[2]

Investigations

1. Transvaginal ultrasonography ( TVUS): Endometrial polyps appear as a hyperechogenic lesion with regular contours. TVUS has a reported sensitivity of 19%–96%, specificity of 53%–100%.
2. Saline infusion sonography or Sonohysterography: is the gold standard for diagnosing endometrial polyps’ increases contrast of the endometrial cavity enabling the viewing size, location and other features of endometrial polyps. Endometrial polyps appear as echogenic smooth masses.
3. Hysteroscopy: this could be both diagnostic and therapeutic, as the polyps could be removed as they are visualized.
4. Confirmation by histopathology of the resected specimen.

Treatment

Expectant Management: Small polyps that are asymptomatic may resolve without treatment.

Medication: Certain hormonal medications, including progestins and gonadotropin-releasing hormone agonists (GnRH), may reduce symptoms of the polyp. However, taking such medications is usually a short-term solution as symptoms typically recur once medication is stopped. Also GnRH analogues cannot be taken for a long time due to its side effects.

Surgical removal: During hysteroscopy, instruments inserted through the hysteroscope are used to remove polyps (polypectomy). The removed polyp will likely be sent to a laboratory for microscopic examination.

Complication

1. Infertility: A major complication of endometrial polyps is infertility.
2. Cancer: Approximately 5 % of endometrial polyps are malignant. Data shows that the incidence of polyps that were malignant was significantly higher in postmenopausal compared with premenopausal women, and higher in women who had symptoms of bleeding than in women who did not.

References

[1] Indraccolo U, Di Iorio R, Matteo M, Corona G, Greco P, Indraccolo SR. The pathogenesis of endometrial polyps: a systematic semi-quantitative review. Eur J Gynaecol Oncol. 2013;34(1):5-22. PMID: 23589993.

2. DeCherney, Alan H.; Lauren Nathan (2003). Current Obstetric & Gynecologic Diagnosis & Treatment. McGraw-Hill Professional. p. 703. ISBN 0-8385-1401-4

3.