An Overview of Endometrioma

Endometriomas, also called ovarian endometriomas, are a type of cyst that can form when endometrial tissue grows in the ovaries. They are sometimes called "chocolate cysts" because they are filled with a dark brown fluid consisting of old menstrual blood and tissue.

These cysts are benign (except in very rare cases) and may occur in one or both ovaries. Endometrioma is part of a condition known as endometriosis, in which the endometrial tissue that lines the uterus grows outside the uterus.

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Symptoms of Endometrioma

Endometriomas may or may not cause symptoms. When symptoms do occur, they are the same as the symptoms of endometriosis.

These may include:


Among the potential complications of endometrioma are:

  • Infertility
  • Ovarian cancer (very rare)
  • Obstruction of the urinary tract or bowel
  • Chronic pelvic pain, which may be debilitating

One of the more serious complications of endometrioma is when one of the cysts ruptures.

Signs of a ruptured cyst include:

  • Pain with fever and vomiting
  • Sudden, severe abdominal pain
  • Faintness, dizziness, or weakness
  • Rapid breathing
  • Bleeding

If an ovarian endometrioma ruptures, you may experience severe, sudden abdominal and pelvic pain on the side where the cyst is located. If you have these symptoms or suspect you may have a ruptured cyst, seek medical attention immediately.


Endometriosis is closely linked with infertility. As many as 50% of women with endometriosis and endometriomas have difficulty getting pregnant. Among women who are infertile, about 30% have endometriosis.

It is not known exactly how these conditions impair fertility, but experts think the increased risk may be due to:

  • The "ovarian reserve," or the number of eggs available for fertilization, may be decreased due to the hormonal effects of the cysts.
  • Inflammation, which involves immune cytokines can interfere with the functions of the sperm and egg cells, making fertilization more difficult.
  • Embryos that form may not be viable due to the fluid in the cysts.


Researchers suggest that some cysts may form as a result of retrograde menstruation, which may also contribute to endometriosis. Ovarian endometrioma is found in up to 17% to 44% of women with endometriosis.

In retrograde menstruation, some of a women’s menstrual blood flows back into her body during her period instead of out through the cervix and vagina. The endometrial cells are carried backward through the fallopian tubes to the ovaries and pelvic cavity, where they implant and cause endometriosis.

With endometrioma, retrograde menstruation results in endometrial tissue being trapped in the cysts, causing inflammation.

There is some evidence suggesting that an autoimmune response can contribute to endometrioma, whereby the endometrial tissue that normally forms during menstruation may incite an inflammatory response leading to scarring and diseased tissue in the pelvis.


Your healthcare provider may consider a diagnosis of endometrioma if you have endometriosis and are experiencing symptoms or have unexplained fertility. A cyst can sometimes be felt during a pelvic exam.


Ultrasounds are good at identifying the presence of cysts, but they might not be able to determine the exact type of cyst you have. There are several different types of ovarian cysts, including follicle cysts, corpus luteum cysts, dermoid cysts, and cystadenomas, most of which are more common than endometriomas.


A needle biopsy starts with an ultrasound to locate the exact location of the cyst. A thin, hollow needle and a syringe are inserted in the cyst to extract tissue and fluid. The fluid and tissue samples are then examined under a microscope to determine if they contain endometrial cells, which is a key indicator of endometrioma.


Your healthcare provider will develop a treatment plan for endometrioma depending on several factors, including your age, your symptoms, whether one or both ovaries are affected, and your plans for having children going forward.

Observation and Monitoring

Cysts that are not causing symptoms are usually not treated. Instead, your healthcare provider may take a watch-and-wait approach.


Similar to the lining of the uterus, endometriosis responds to fluctuations in the hormones progesterone and estrogen. For women who are not actively trying to conceive, hormonal forms of birth control, such as birth control pills, NuvaRing, or a hormonal birth control patch, can regulate hormone function, slow down cyst growth, and help reduce pain.


Surgery to remove cysts—called ovarian cystectomy—is recommended for women who have painful symptoms, large cysts, cysts that might be suspect for cancer, or infertility. This procedure involves making small incisions in the belly and inserting a laparoscope—a thin, long tube with a camera and light—to help the healthcare provider see and remove the cyst.

In women who are planning to conceive, the risks and benefits of an ovarian cystectomy have to be weighed carefully, as the procedure can potentially have negative effects on ovarian function and decrease the likelihood of conception, either naturally or with in vitro fertilization.

On the other hand, leaving endometriomas in place before undergoing treatment with IVF increases the risk of pelvic infection after a woman's eggs are extracted, and can also contaminate the culture in which the egg and sperm are joined.

Complementary Therapies

While this area hasn't been studied extensively for women who have endometrioma, some complementary or alternative therapies have been found to help some women with endometriosis. These include acupuncture, Chinese medicine, vitamins, and dietary supplements.

Always talk to your healthcare provider before trying an alternative treatment.


In addition to medical approaches, you may find some relief from the symptoms and stress of endometrioma by adjusting certain aspects of your lifestyle.


In recent years there has been a lot of interest in the role of inflammation in many diseases. Diet can affect inflammation.

Studies have shown that consuming a diet consisting largely of fresh vegetables, fresh fruit, and foods high in omega-3 fatty acids (such as salmon, halibut, walnuts, and flaxseeds) can significantly reduce the risk of endometriosis, while frequent consumption of red meat increases the risk.


Exercise may relieve the pain of endometrioma by encouraging healthy circulation, decreasing excessive estrogen production, relieving stress, and releasing pain-relieving endorphins in the brain.

Stress Management

The pain and potential infertility of endometrioma can negatively affect all aspects of your life, including work, family, and relationships. Exercising, getting adequate sleep, and seeking individual talk therapy and/or a support group for women with endometriosis may all be effective ways to reduce stress.

Frequently Asked Questions

What is an endometrioma?

A endometrioma is a type of cyst formed when endometrial tissue grows in the ovaries. They are sometimes called "chocolate cysts" because they are filled with a dark brown fluid consisting of old menstrual blood and tissue.

What causes endometrioma?

The exact cause of endometrioma is not known, but one theory is that the condition is caused by retrograde menstruation, in which menstrual blood and tissue are carried backward through the fallopian tubes to the ovaries instead of being expelled from the body.

What kind of healthcare provider treats endometrioma?

A gynecologist is a specialized doctor who can diagnose and manage endometrioma.

What is a chocolate cyst?

A chocolate cyst is another name for an endometrioma, a type of ovarian cyst that can form in the ovary.

A Word from Verywell

Cysts associated with endometrioma can be painful and cause stress, especially for women who are planning to have children. Fortunately, there are many treatment options as well as lifestyle measures that can manage the pain and reduce the risk of complications.

Because endometriomas, as well as the surgery used to treat them in some cases, can significantly affect fertility, it's important to talk to your healthcare provider if you are trying to conceive.

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9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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