Endometrial Polyp -Symptoms, Complications, Diagnosis, and Treatment.

Introduction

Endometrial polyps also called uterine polyps are common in women who are going through or those who have completed menopause. However, uterine polyps can also affect women of reproductive age. These polyps are benign (non-cancerous) growths attached to the endometrium (inner lining of the uterus). Though the endometrial polyps are usually non-cancerous, some polyps can be cancerous or progress to become cancerous.

What Are Endometrial Polyps?

Endometrial polyps are abnormal growths in the endometrium of the uterus. The polyps contain glands, stroma, and blood vessels that project from the endometrium to occupy and fill the uterine cavity. It can affect women at the reproductive and post-menopausal phase of life. The size of the endometrial polyp can range from 5 mm (millimeters) to a large polyp that fills the entire cavity.

The polyps are usually located in the fundus (the hollow part of the uterus that is in the top, away from the cervical opening), especially in the corneal area (a funnel-shaped portion in the upper uterine body which receives the insertion of the fallopian tubes). The endometrial polyp is referred to as pedunculated, if it is attached to the surface of the uterus by a narrow elongated pedicle (a stalk-like structure that connects an organ or other part to the body).

The polyps are called sessile, if the stalk is absent and they have a flat base. The polyps appear smooth, spherical, or cylindrical , and are tan to yellow in color. In the presence of endometrial polyps, the endometrium may be normal or become hyperplastic (increased number of cells in an organ or tissue).

What Are the Symptoms of Endometrial Polyps?

Some women with endometrial polyps remain asymptomatic, while some women experience the following symptoms:

• Abnormal uterine bleeding.

• Vaginal bleeding after menopause.

• Frequent, unpredictable, and long menstruation.

• Infertility.

• Bleeding between periods.

What Are the Causes of Endometrial Polyps?

The exact cause of endometrial polyps are unknown. The endometrial polyps are thought to be related to estrogen stimulation, which can be due to an increase in the concentration of estrogen receptors.

The following risk factors can increase the formation of endometrial polyps:

• Increased estrogen production.

• Exogenous estrogen administration in hormone replacement therapy.

• Tamoxifen drug administration for breast cancer treatment.

• Hypertension.

• Obesity.

• The presence of Lynch syndrome (a genetic condition that leads to cancer) or Cowden syndrome (a genetic disorder that presents with multiple non-cancerous growths and increased risk for certain types of cancers).

How Do Endometrial Polyps Develop?

The exact cause of endometrial polyps are not known. Several theories were proposed to explain the development of endometrial polyps. It was thought that estrogen stimulation, and decreased expression of progesterone can result in the development of endometrial polyps. Some researchers thought that an imbalance between the mitotic activity and apoptosis plays a role in the development of endometrial polyp.

Other theories suggest that chromosomal abnormalities cause formation of endometrial polyps. It was found that Tamoxifen drug used in the treatment of breast cancer has estrogenic effects on the uterus. It promotes the growth of polyps by inhibiting apoptosis.

Endometrial polyps can develop as a result of localized chronic inflammation in the endometrium. Chronic inflammation causes the formation of new blood vessels. Inflammation is initiated and controlled by mast cells. These mast cells are higher in endometrial polyps. These cells induce the formation of blood vessels and an increase in the blood vessel density is considered a polyp. The polyps can be inflammatory in nature or hormone dependent.

What Are the Complications Associated With Endometrial Polyps?

Endometrial polyps can cause various complications, including abnormal uterine bleeding, infertility due to implantation failure, and malignant transformation. Abnormal bleeding is caused due to stromal congestion within the polyp resulting in venous stasis and apical necrosis. The implantation failure can be due to mechanical obstruction or biochemical effects of the polyps.

A small fraction of endometrial polyps undergo malignant transformation. The common cancer subtypes associated with endometrial polyps are endometrioid adenocarcinoma and serous adenocarcinoma. The risk of developing cancer is associated with factors such as the size of the polyp (polyps above 15 mm), age, hypertension, obesity, hormone replacement therapy, and the use of Tamoxifen.

How Are Endometrial Polyps Diagnosed?

Several methods are available to diagnose endometrial polyps.

It includes the following:

• Transvaginal Ultrasonography: An ultrasound probe is inserted through the vagina to reach the uterine cavity. The polyps are visualized as hyperechogenic lesions with regular borders. Sometimes, cystic glands are visible within the polyp.

• Color-flow or Power Doppler Study: Color-flow Doppler is used to determine the single feeding vessel of the endometrial polyps. It aids in the identification of the typical single vessel pattern of endometrial polyp, in contrast to multiple vessel patterns in hyperplasia and malignant lesions.

• Sonohysterography or Saline Infusion Sonography: Sonohysterography increases the contrast of the endometrium and helps in determining the size and location of the endometrial polyps. Saline infusion may increase the sonographic details. It also helps in diagnosing myometrial and adnexal abnormalities.

• Histological Examination: The histological examination of the biopsied tissue reveals the presence of stroma with a dense fibrous tissue, glandular abnormalities, and thick-walled blood vessels. The polyps appear similar to cystic hyperplasia during every stage of the menstrual cycle.

How Are Endometrial Polyps Treated?

The treatment of endometrial polyps depend on the symptoms, fertility issues, and malignancy.

The treatment options include the following:

• Conservative Surgery - Hysteroscopic polypectomy is the mainstay treatment for the removal of endometrial polyps. Dilation and curettage along with the use of polypectomy forceps help in investigating the abnormalities. However, it is associated with limitations such as missing a polyp.

• Conservative Non-surgical Treatment - Asymptomatic women with polyps less than 10 mm size require observations alone. Hormone combined therapy in postmenopausal women may reduce the development of endometrial polyps.

• Levonorgestrel Intrauterine System - The Levonorgestrel intrauterine system prevents the development of endometrial polyps in women under estrogen replacement therapy and Tamoxifen drug.

• Dienogest and Danazol - Dienogest and Danazol are used to prepare the endometrium in patients undergoing hysteroscopic surgery. It reduces the thickness of the endometrium and the severity of the bleeding during surgery.

Conclusion

Endometrial polyps are common in women and are a significant cause of infertility. It also acts as a precursor to malignancy. Early diagnosis and treatment is essential to prevent the progression of the polyps and the risk of complications.