Endometrial Polyps
Endometrial polyps are hyperplastic proliferations or excessive growths of the endometrial glands and the tissue surrounding a blood vessel. They form projections that protrude from the surface of the endometrium, the inner lining of the uterine cavity responsible for housing the embryo during pregnancy and for menstrual cycles.
Due to advances in the use of transvaginal ultrasound and diagnostic hysteroscopy, the diagnosis of this condition has increased. Polyps are the most frequently found pathology during diagnostic hysteroscopy and are responsible for the majority of surgical hysteroscopies.
Causes
Imbalance in estrogen/progesterone levels:
These hormones regulate the proliferation and menstrual shedding of the endometrium. Higher levels of hormone receptors have been detected within polyps compared to the surrounding normal endometrium. Both hormones contribute to the irregular growth of endometrial glands and their vascularization, leading to the formation of polyps.
Symptoms
Most polyps are asymptomatic and are usually diagnosed during a routine gynecological examination. When they become symptomatic, they generally cause abnormal uterine bleeding, which is the most common symptom and occurs in 64% to 88% of women with polyps.
Intermenstrual bleeding is the most frequent symptom in premenopausal women with endometrial polyps. The amount of bleeding is usually small and may present only as spotting.
Rarely, an endometrial polyp may be visible during a speculum examination at the external cervical opening. Prolapsed polyps may be symptomatic or asymptomatic. Postcoital bleeding is also common, and polyps are frequently found in asymptomatic patients being evaluated for infertility.
Postmenopausal bleeding is another common presentation; some postmenopausal women with polyps experience intermittent bleeding during hormone therapy.
RISK FACTORS
The frequency of occurrence increases with hypertension, diabetes, obesity, and age over 40, with the highest prevalence between 45 and 50 years of age. Certain medications such as tamoxifen—commonly used to prevent recurrence in some types of breast cancer—also increase the risk.
CLASSIFICATION
Polyps can be classified as:
- Functional or Typical (20%) – Similar in appearance to normal endometrium.
- Hyperplastic (35%) – Showing changes that indicate accelerated growth.
- Atrophic (40%) – Showing changes with slowed growth or regression; commonly found in menopausal patients.
- Malignant (1–5%) – Containing cancerous cells within the polyp.
The term pseudopolyp refers to thickened areas of the endometrium that resemble a polyp, measure less than 1 cm, and disappear after menstruation because they lack their own blood vessels.
Regarding the risk of malignancy, approximately 95% of endometrial polyps are benign. A systematic review of 17 observational studies including more than 10,000 women reported that the incidence of malignant or hyperplastic polyps was significantly higher in postmenopausal women compared to premenopausal women (5.4% vs. 1.7%), and in women with bleeding compared to those without bleeding (4.2% vs. 2.2%).
Diagnosis
Ultrasound can diagnose the presence of an endometrial polyp either by directly visualizing the lesion and its vascularization using color Doppler, or indirectly by detecting an area of abnormal endometrial growth.
Other diagnostic techniques include hysterosalpingography (also known as an X-ray of the fallopian tubes) and sonohysterography, which is an ultrasound performed after infusing fluid into the uterus.
The gold standard for diagnosing polyps is hysteroscopy, as it allows confirmation and localization of the lesion, detailed evaluation of the endometrium, and histopathological diagnosis through biopsy of both the polyp and the endometrium. It has a sensitivity and specificity of 95–100%. This procedure also enables early detection of conditions such as endometrial hyperplasia or various types of endometrial carcinoma.
Techniques used before hysteroscopy, such as uterine curettage, failed to diagnose more than 10% of polyps.
Strong evidence shows that in postmenopausal women with bleeding, thickened endometrium, and a negative blind endometrial biopsy (without hysteroscopic visualization), 3% had undiagnosed endometrial cancer and another 3% had endometrial hyperplasia with atypia within polyps.
Treatment
In general, removal is indicated for any symptomatic polyp, meaning those that cause bleeding or infertility. In premenopausal patients with completely asymptomatic polyps that appear functional and measure less than 10 mm, a watchful waiting approach may be appropriate, with ultrasound monitoring every six months to assess growth.
Hysteroscopic polypectomy is a simple procedure, usually performed on an outpatient basis or as day surgery. Patients may experience light vaginal bleeding for a few days after the procedure, as well as mild discomfort that typically improves with anti-inflammatory medication (NSAIDs). Most patients return to their normal activities within a few days.