Continuing Education Activity

Endometrial polyps refer to overgrowths of endometrial glands and stroma within the uterine cavity. Endometrial polyps vary in size from a few millimeters to several centimeters in diameter. Polyps may be found as a single lesion or multiple lesions filling the entire endometrial cavity. This activity reviews the evaluation and management of endometrial polyps and explains the role of the interprofessional team in evaluating and treating patients with this condition.

Objectives:

• Review the risk factors for developing an endometrial polyp.

• Outline the typical presentation of a patient with endometrial polyps.

• Describe the typical imaging findings associated with endometrial polyps.

• Explain the importance of collaboration and communication among the interprofessional team to ensure the appropriate selection of candidates for surgical management of endometrial polyps and improve outcomes.

Introduction

Endometrial polyps refer to overgrowths of endometrial glands and stroma within the uterine cavity. Endometrial polyps vary in size from a few millimeters to several centimeters in diameter. Polyps may be found as a single lesion or multiple lesions filling the entire endometrial cavity. Endometrial polyps may be diagnosed at all ages; however, peak incidence occurs between the age of 40 to 49 years old. Although these polyps are considered benign, there is a small risk of malignant transformation.

Etiology

Endometrial polyps are localized overgrowths of the endometrial glands and stroma that protrude out of the endometrium. The definite etiology of endometrial polyps is unknown. However, endometrial polyps are associated with endometrial hyperplasia; therefore, unopposed estrogen is considered to be a risk factor.[1] Other mechanisms that have been associated with the development of polyps include increased endometrial aromatase activity, TGF-beta, VEGF, BCL-2, and genetic factors.[2][3][4][5] Endometrial abnormalities, including the development of polyps, are associated with chronic tamoxifen therapy and occur in 20% to 35% of females.[6] 

A majority of polyps are benign; however, malignant transformation can occur in 0 to 13%.[7] Malignancy in an endometrial polyp is related to a patient’s age and menopausal status. The prevalence of malignant endometrial polyps in symptomatic postmenopausal females is 4.47% compared with 1.51% in an asymptomatic postmenopausal female.[8] Additional risk factors for malignant endometrial polyps include age greater than 60, large-sized polyps, menopause status, symptomatic bleeding, and polycystic ovarian syndrome.[9]

Epidemiology

Endometrial polyps occur in all age groups, with a peak incidence between the age of 40 to 49. The prevalence of endometrial polyps in reproductive-aged women with abnormal uterine bleeding is estimated between 20 to 40 percent.[10] Endometrial polyps are found in approximately 10 percent of women at the time of autopsy. Premenopausal females are less likely to have malignant endometrial polyps compared to postmenopausal females.[11]

Histopathology

Polyps are endometrial epithelial proliferations comprised of vascular, glandular, fibromuscular, and connective tissues.[1] Endometrial polyps are primarily covered by epithelial tissue superficially and contain a largely vascular core. Polyps may be classified as sessile, pedunculated, or prolapsing. A prolapsed polyp may contain areas of squamous metaplasia, infection, or ulceration. A majority of polyps will be composed of the endometrium that differs from the surrounding endometrium and does not respond to cyclic hormonal changes. Other histological findings include carcinomatous, atrophic, or hyperplastic.[1]

History and Physical

Patients with endometrial polyps may be asymptomatic, or the most common symptom is abnormal uterine bleeding.[1] Other associated symptoms include abdominal pain, pelvic pain, or infertility. One in four reproductive-aged women with abnormal bleeding will have endometrial polyps within the cavity. For any patient with abnormal uterine bleeding, it is important to identify the underlying cause, severity, any associated symptoms, and comorbidities. Obtaining a comprehensive medical and surgical history is crucial to exclude other causes of abnormal uterine bleeding. Although there is not a diagnostic bleeding pattern for endometrial polyps, a detailed history of the patient’s bleeding pattern should be obtained. The most commonly reported patterns include menorrhagia and intermenstrual spotting.

Tamoxifen, often used in the treatment of breast cancer, has agonistic or antagonistic effects on tissue containing estrogen receptors. Tamoxifen works as an anti-cancer agent on breast tissue; however, it acts as a carcinogenic agent on endometrial tissue.[12] Chronic tamoxifen use has been associated with the development of endometrial polyps, with an incidence of 20% to 35%.[6] Furthermore, hormone replacement therapy for menopausal symptoms may also be associated with the formation of endometrial polyps with reported symptoms of irregular bleeding and thickened endometrium on ultrasound.[13] 

A general physical exam should be performed along with a bimanual exam and sterile speculum exam during the clinic visits. The cervix and vaginal vault should be fully examined to rule out other structural causes for the patient’s symptoms. A pedunculated endometrial polyp may be visualized from the external os.

Evaluation

Transvaginal ultrasound is the most common and efficient technique in imaging pelvic structures. Findings on ultrasound may appear nonspecific with diffuse or localized, echogenic endometrial thickening.[14] In patients with symptoms of postmenopausal bleeding, an endometrial thickness of less than 4 mm is associated with an atrophic endometrium. However, increased endometrial thickness greater than 4 mm is related to endometrial pathology, including polyps.[13] The location of the polyp, number, and diameter does not correlate with the reported symptoms.[15] 

Another method to evaluate the endometrial cavity is saline-infusion sonography (SIS). This modality involves instilling about 5 to 30 mL of warmed saline into the uterine cavity using a thin catheter during the proliferative phase of the menstrual cycle. Polyps are better visualized with fluid outlining the mass. Contraindications include active uterine or cervical infection and pregnancy. SIS provides a better evaluation of the adnexa and cornua compared to transvaginal ultrasound. In addition, SIS provides better differentiation between submucosal fibroids and endometrial polyps by visualizing the location in relation to the endometrial layer. A polyp will be seen arising from the endometrial layer, and a submucosal fibroid will be visualized under this layer. Other methods of evaluation include hysterosalpingograms or hysteroscopy.

More importantly, these methods will not provide tissue diagnosis. Tissue sampling should be considered due to the risk of malignancy associated with endometrial polyps. To obtain tissue diagnosis, an endometrial biopsy, dilation, and curettage (D&C) or hysteroscopic polypectomy must be completed. Blind tissue sampling with endometrial biopsy or D&C is inaccurate in the diagnosis of endometrial polyps and should only be used in settings where hysteroscopic treatment is unavailable.[16]

Laboratory studies are also considered in the evaluation of abnormal uterine bleeding. Studies should include a urine pregnancy test, a complete blood count, and a coagulation panel to rule out anemia and coagulopathy.

Treatment / Management

For asymptomatic and low-risk patients, endometrial polyps can be managed conservatively with observation. Incidental endometrial polyps may regress spontaneously if left untreated. In one trial, 29% of endometrial polyps resolved spontaneously after 1 year in premenopausal patients.[17] Conservative management includes periodic assessment of polyp growth with ultrasound. Medical management with hormonal therapy has limited support in the literature and cannot be recommended at this time.[16]

Hysteroscopic polypectomy is considered the standard treatment of an endometrial polyp. Polyps may be associated with underlying endometrial pathology; therefore, both the polyp and the surrounding endometrium should be histologically evaluated. Benign polyps have been found in 20% of cases with a diagnosis of endometrial carcinoma. The timing of hysteroscopic polypectomy is unclear for asymptomatic and low-risk patients. A retrospective study performed to determine the appropriate timing of polypectomy found no incidence of malignancy on histologic specimens and concluded that it is unclear when to perform routine polypectomy in asymptomatic females.[18] Larger sized polyps measuring greater than 1.5 cm in length are less likely to resolve spontaneously, and polypectomy could be considered in symptomatic patients.[17]

Hysterectomy is a radical surgical option that eliminates the risk of polyp recurrence and the potential for malignancy. Hysterectomy is associated with a significantly greater risk to the patient and cost and should only be contemplated after extensive patient counseling.[16]

For patients with anemia secondary to abnormal uterine bleeding, consider daily iron supplementation.

Differential Diagnosis

The differential diagnosis includes submucosal leiomyoma, adenomyoma, retained products of conception, endometrial hyperplasia, endometrial carcinoma, and uterine sarcomas.

Prognosis

After hysteroscopic polypectomy, significant improvement in intermenstrual bleeding has been reported.[19] Treatment after hysteroscopic polypectomy is effective with low recurrence in patients who initially presented with a fewer number of polyps.[1][19] The recurrence rate in histologically confirmed polyps is approximately 2.5% to 3.7%.[16] Recurrence rates are further decreased if hysteroscopic polypectomy is combined with endometrial ablation or insertion of a levonorgestrel-releasing intrauterine device.[20] However, there is limited data to support these recommendations, and currently, the use is limited to research protocols.[16] In patients with tamoxifen-associated polyps, a levonorgestrel intrauterine device (IUD) has been shown to decrease polyp formation and may be considered as part of the management plan.[21]

Spontaneous pregnancy and delivery at term rates in some studies increased after the hysteroscopic polypectomy. There was no statistical difference in fertility rates between patients having polyps less than or equal to 1 cm and patients having greater than 1 cm polyps or multiple polyps. The spontaneous abortion rate in the first trimester of pregnancy showed no statistical difference between patients with small or bigger/multiple polyps.[22]

Complications

After hysteroscopic polypectomy, the collected specimens should be submitted to pathology for evaluation. On follow-up of specimen pathology, polyps may have evidence of malignancy, and referral to gynecology oncology is recommended for further management. Complications associated with hysteroscopic polypectomy are rare, and the risk of intrauterine adhesion is low.[23]

Conflicting data is available on the relationship between endometrial polyps and the risk of infertility. A prospective, randomized controlled trial showed that hysteroscopic polypectomy before intrauterine insemination is an effective measure and improved pregnancy rates.[24] Also, the prevalence of endometrial polyps is significantly higher in infertile patients with Fallopian tube obstruction than in patients with Fallopian tube patency.[25] In contrast, a retrospective review of patients who received in vitro fertilization (IVF) with known polyps during IVF cycles found no difference in pregnancy rates, miscarriage rates, or live birth rates.[26] Currently, the expert recommendation is the removal of endometrial polyps prior to in-vitro fertilization.

Deterrence and Patient Education

Education should focus on the etiology and the management of abnormal uterine bleeding. A majority of polyps have benign pathology however, patients should also be counseled on the possible risk of malignancy. Discussion of malignancy carries a potentially harmful risk to the mental well-being of patients. Quality of life and future fertility is also impacted by the presence of endometrial polyps. Patients should be educated on the possibility of recurrence and modifiable factors to decrease these risks.

Enhancing Healthcare Team Outcomes

Endometrial polyps can have a negative impact on the quality of life and mental health of patients who have a poor understanding of the disease. Patients should be counseled on the disease pathology keeping in mind that terms like “lesion” or “neoplasm” may cause excessive concern for the patient.

Symptoms of abnormal uterine bleeding should be fully evaluated to rule out more serious etiologies, like malignancy. Endometrial polyps may be managed conservatively for low-risk patients or can be treated surgically. Recurrence risks should be discussed, and appropriate candidates may benefit from endometrial ablation and levonorgestrel intrauterine devices to decrease these risks. In cases of surgical management, an anesthesia consult should be considered for high-risk patients. Specialized surgical nurses will be responsible for preparing the patient before and after the procedure, intraoperative positioning, and arranging the correct surgical supplies. Nursing staff can follow up postoperatively to assess treatment success and inform the care team of any concerns.

All healthcare professionals should counsel the patient on the benefits, risks, alternatives, and outcomes of the procedure. Emphasis should be placed on communication and collaboration among team members to deliver safe and patient-centered care.