Ovarian Endometrioma (Chocolate Cyst)

What is an endometrioma?

Endometriosis is a condition where tissue that’s similar to the tissue that grows inside your uterus is growing outside your uterus. It can cause painful periods, pelvic pain and impact your ability to get pregnant. When this tissue attaches to your ovary, it’s called an endometrioma and can be filled with brown, chocolate-like fluid. An endometrioma can cause irritation and attach to other organs. If you have an endometrioma, it can be a sign that you have a more severe form of endometriosis.

If the endometrioma causes you pain, becomes large or affects your fertility, there are treatments available to help you.

How common are ovarian endometriomas?

About 10% of people who menstruate have endometriosis, and about 17% to 44% of those people develop ovarian endometriomas.

What are the symptoms?

Pain or tenderness in your pelvis is the most common symptom of an ovarian endometrioma. This pain can happen at any time and not just when you’re on your period. You may notice other symptoms, too, such as:

• Menstrual periods that are very painful
• Pain during sexual intercourse (dyspareunia)
• Pain when you’re peeing or pooping
• Feeling the urge to pee more
• Back pain
• Nausea and vomiting
• Bloating

How big are endometriomas?

They can be very small, grow very large and can involve one or both ovaries.

What causes an ovarian endometrioma?

It’s not known what exactly causes an endometrioma. One theory is that endometriosis happens because some of the endometrial-like tissue that you shed when your menstruate flows backward (retrograde menstruation). Instead of leaving your body through your vagina, some of the tissue travels back through your fallopian tubes and onto your ovaries. This tissue thickens and bleeds during each menstrual cycle, leading to inflammation and the formation of an endometrioma cyst.

What are risk factors for ovarian endometrioma?

Endometriomas are a type of endometriosis. Anyone who menstruates can get endometriosis. Some of the risk factors for endometriosis are:

• Family history of endometriosis
• The age you first start having periods (people who begin menstruating before 11 may be at a higher risk)
• The length of your menstrual cycle (less than 27 days between periods) and the duration of flow (bleeding for more than seven days)
• Abnormalities in your uterus or fallopian tubes

What are the complications of endometriomas?

In most cases, endometriomas are signs of a more advanced stage of endometriosis. Other than severe pelvic pain, some of the complications of ovarian endometriomas are:

• Infertility due to scar tissue and inflammation of your ovaries and fallopian tubes
• Bowel and bladder problems such as a complete blockage, chronic constipation or needing to pee more frequently
• Endometrioma rupture, when the cyst opens and leaks, causing additional pain
• Increased risk of ovarian cancer

With a rupture, you’re likely to also have a fever, severe abdominal pain, weakness and other symptoms.

Ovarian endometriomas can become cancerous, but this is rare. Your provider may monitor your cysts and discuss treatment options if there’s concern that an ovarian endometrioma could become cancerous.

How are ovarian endometriomas diagnosed?

Physical exams and imaging procedures can help diagnose an ovarian endometrioma. If the cyst is especially large, your provider may notice it during a pelvic exam. A transvaginal ultrasound or MRI will provide more information.

To officially diagnose an ovarian endometrioma, a surgeon removes the cyst and sends it to a lab for examination. Usually, this happens during a laparoscopy. During this procedure, your provider makes tiny cuts in your abdomen and inserts a camera tube called a laparoscope. Using this tube, your surgeon can see the cyst, remove a sample of it for testing (biopsy) or remove it entirely. The sample is sent to a lab where a pathologist examines it.

What other tests will be done to diagnose an ovarian endometrioma?

A provider may order other tests to rule out conditions that may be causing your symptoms. Your provider may order:

• A complete blood count (CBC). Your blood cells let your provider know if you have an infection or if you have too few of them (anemia). People with ovarian endometriomas often have low red blood cell counts because of the heavy bleeding that can come with endometriosis.
• A urinalysis. This test can let your provider know if your symptoms are from a urinary tract infection (UTI).
• Sexually transmitted infection (STI) tests. Your provider can rule out whether an STI is causing your symptoms.

What is the treatment for ovarian endometriomas?

There isn’t a cure for ovarian endometriomas, but a surgeon can remove them if they cause unpleasant symptoms or pose risks to your health. Treatment options include:

• Monitoring. You and your provider may choose to monitor your cysts if they’re small and not causing symptoms.
• Surgery. Your provider may recommend a laparoscopy if you have ovarian endometriomas that are painful, growing or bigger than 4 centimeters. Removing the cyst not only helps improve your symptoms but reduces complications like rupture or infertility.
• Medications. Your provider may also recommend medications to regulate hormonal fluctuations that stimulate endometriosis. Medications such as birth control pills, patches, vaginal rings and non-birth control options can help manage symptoms and improve your quality of life.

The best treatment for you depends on lots of factors, like your age, your symptoms and your plans for becoming pregnant. Weigh the pros and cons of your options with your provider to decide the best plan for you.

What happens if you don’t remove an endometrioma?

You don’t always have to remove an endometrioma. Ovarian endometriomas that are small and don’t cause pain may not need treatment. In this case, your provider may recommend monitoring the cyst over time.

Can ovarian endometriomas grow back?

Yes, they can come back even after treatment. The rate of recurrence varies depending on factors like the size of the original endometrioma, your age and the type of treatment you had. About 1 in 4 people will see an endometrioma return.

How can I prevent getting an ovarian endometrioma?

There’s no way to prevent an ovarian endometrioma from forming.

What can I expect if I have an ovarian endometrioma?

Having ovarian endometriomas means that you have moderate to severe endometriosis. You should work with your provider to manage any symptoms you’re experiencing because of endometriosis. For example, you may need help managing pain or need to seek treatment for fertility issues (if you’re trying to get pregnant).

When should I see my healthcare provider?

Contact a healthcare provider if you have pelvic pain or other symptoms of an ovarian endometrioma. They can perform an exam and order tests to see if an ovarian endometrioma is the source of your painful symptoms.

When should I go to the ER?

You should seek emergency care if you have an ovarian endometrioma that bursts. Pay attention to these warning signs:

• Fever
• Vomiting
• Feeling weak or dizzy, like you’re about to faint
• Severe pain in your abdomen that happens without warning

What is the difference between an ovarian cyst and an endometrioma?

The differences between the two conditions are what’s inside the cyst and what causes the cyst. In the case of an endometrioma, the cyst contains old blood. An ovarian cyst can contain blood, tissue and other types of clear, brown or red fluid. The other difference is that an ovarian endometrioma is unique and specific to endometriosis. Ovarian cysts can develop for many different reasons other than endometriosis.

Is endometrioma worse than endometriosis?

One isn’t necessarily worse than the other. Endometriomas are a type of endometriosis. Having endometriomas usually means you have a severe form of endometriosis.