An endometrial polyp is an outgrowth of endometrial tissue into the uterine cavity. Polyps are a common cause of abnormal uterine bleeding (AUB) and should be considered in the differential during the work-up of a patient with heavy or irregular menses.

The precise mechanism of formation of endometrial polyps is unclear, although it appears to represent simple endometrial growth into pedunculated masses. They most commonly occur in reproductive-aged women, and incidence increases with age. Tamoxifen, obesity, and postmenopausal hormone therapy are associated with increased rates of endometrial polyps.

The incidence of endometrial polyps is difficult to determine as polyps may be asymptomatic, but pathologic examination of post-hysterectomy uteri reveal a prevalence of 10%-24%.

Polyps are most commonly diagnosed during the work-up of AUB, although they may also be discovered incidentally by ultrasound, during surgery involving the uterine cavity (eg, hysteroscopy, cesarean section), or occasionally during pelvic exam if the polyp is protruding through the cervix.

Although endometrial polyps are generally benign (less than 5% are malignant although some are hyperplastic [precancerous]), they do warrant removal both to rule out malignancy and to treat symptoms. Pathologic evaluation is especially recommended in women with an increased risk of endometrial cancer (eg, postmenopausal status, obesity, tamoxifen exposure). Risk of hyperplasia or malignancy increases significantly when the patient is postmenopausal.