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Endometrioid cyst
Last reviewed: 07.07.2025

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An endometrioid cyst is a type of ovarian cystic formation that differs from functional neoplasms in the mechanism of formation and development. Most often, an endometrioid cyst is formed in both ovaries as a result of the underlying chronic disease - endometriosis. Endometrial cells are capable of spreading to many nearby organs and ducts, they grow and line the vagina, fallopian tubes, ovaries. Such pathological foci are considered hormone-dependent and actively function. With each new menstruation, endometrial cells increasingly grow in the cortical tissues of the ovaries and provoke the formation of neoplasms of a fairly large size. An endometrioid cyst is also called quite figuratively and aptly, characterizing the contents of the cyst cavity - a chocolate cyst. The cavity of the neoplasm contains brown contents, consisting of blood clots that did not find an outlet during menstruation.
Endometrioid cysts are classified as follows:
- Stage I. Small point neoplasms that are localized on the surface of the ovary, they are often also spread in the peritoneum, closer to the rectum. These cysts do not yet have a cavity, they rather resemble swollen endometrioid tissue.
- Stage II. The neoplasm forms on one ovary, develops to a size of 3-5 centimeters, may have smaller neighboring inclusions in the peritoneum, localization is the rectum area. Often accompanied by adhesions, but not yet involving the intestine.
- Stage III. The endometrioid cyst develops into a large formation, causing the formation of a neighboring cyst in the other ovary. The inclusions grow throughout the uterine cavity, capturing the fallopian tubes and most of the peritoneum. The adhesions also involve the appendages and intestines.
- Stage IV. Full-fledged bilateral cystic formations, 5-8 centimeters in size, the growth of inclusions affects the urinary bladder, sigmoid colon, rectum. The adhesive process is diffuse, affecting almost all nearby organs and systems.
Endometrioid cyst: symptoms
A "chocolate" neoplasm is a formation clearly visible on ultrasound imaging with a capsule filled with a viscous, thick, dark-brown mass. The size of the cystic formation is quite large, but rarely exceeds 10-12 centimeters. Symptoms do not appear in the early stages of development due to the prevalence of the process and the non-specificity of the signs. If the neoplasm reaches a size of 3-5 centimeters, nagging pains appear in the lower abdominal region, and a large cystic formation can also cause menstrual irregularities, most often dysmenorrhea. Often, the cause of persistent, chronic infertility can be an undetected endometrioid cyst, which is in the second stage of development. The main sign that the cyst is developing into a pathological form is pain:
- Pain during sexual intercourse, most often during intercourse.
- Pain in the middle of the menstrual cycle, often cramping.
- Pain in the lower abdomen, right and left, radiating to the lumbar region.
- Too long menstruation, heavy bleeding.
- Discharge after menstruation (spotting).
- Dysmenorrhea.
- With the adhesion process, constipation, urinary retention, and flatulence are possible.
The clinical picture of the acute condition is "acute abdomen" with a ruptured cystic formation. Signs are severe pain, diffused throughout the peritoneum, tense abdominal muscles, tachycardia, a drop in pulse and blood pressure, and fainting. This condition is life-threatening and requires emergency surgery.
An endometrioid cyst is a rather threatening disease that can result in peritonitis if the cavity contains pus, the cystic formation ruptures and the contents enter the peritoneum.
Endometrioid cyst: treatment
Even if an endometrioid cyst is diagnosed at the first stage of development, it still needs to be removed surgically. Medicinal conservative therapy, as a rule, does not give the desired result, in addition, an endometrioid cyst can become malignant, that is, develop into a malignant formation. The most effective method of surgical intervention, eliminating the risk of developing an oncological process, is the radical removal of all identified pathological endometriosis foci. Also, depending on the stage of development and the size of the cyst, resection of the ovaries is indicated, or one of them, if the woman is of reproductive age. Laser treatment of the endometrioid cyst, evaporation of pathological areas of endometriosis gives a good result. In pregnant women, small cystic formations are not removed, since they do not pose a serious threat to either the health of the mother or the future baby. If the neoplasm interferes with the course of pregnancy, it is removed using a gentle laparoscopic method.
Endometrioid cysts are easily prevented - you need to undergo a gynecological examination every six months, preferably a comprehensive one, including a visual examination, ultrasound, and colposcopy. A small cystic formation diagnosed in a timely manner, as well as endometriosis, is successfully treated with the help of low-trauma surgery while preserving all the fertile properties of a woman and her reproductive functions.