Endometrioma (Chocolate Cyst)

An endometrioma is a type of cyst that forms on or inside your ovary. It’s usually filled with thick, brown fluid. It’s sometimes called a “chocolate cyst.” Endometriomas can be very small or grow large. They can affect one or both ovaries.

Endometriomas are associated with endometriosis, a condition where tissue similar to the lining of your uterus grows on other parts of your body. Endometriomas may be a sign of severe endometriosis.

Healthcare providers can treat endometriomas that cause pain, become large or affect fertility.

Studies estimate that between 17 and 44 in 100 women with endometriosis develop an ovarian endometrioma.

Symptoms of a chocolate cyst

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

• Severe pain during your period
• Pain during sex
• Pain when you’re peeing or pooping
• Feeling the urge to pee more
• Back pain
• Nausea and vomiting
• Bloating

Endometrioma causes

One theory is that they form because some of the tissue-like lining that sheds during your period flows backward instead of leaving your body. This is called retrograde menstruation. The tissue can travel through your fallopian tubes and attach to your ovaries.

Over time, the tissue can thicken and bleed with each menstrual cycle. This may lead to irritation, inflammation and a cyst forming.

Risk factors

Endometriomas are cysts caused by endometriosis. Some of the factors that can raise your risk of endometriosis are:

• Family history of the condition
• Starting your period at a young age (before age 11)
• Having periods fewer than 27 days apart or bleeding for more than seven days
• Abnormalities in your uterus or fallopian tubes

Complications of chocolate cysts

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

• Infertility due to scar tissue and inflammation of your ovaries and fallopian tubes
• Bowel and bladder problems like constipation or urinary frequency
• Endometrioma rupture, when the cyst opens and leaks (rare)
• Increased risk of ovarian cancer (rare)

Ovarian endometriomas can become cancerous, but this is rare. Your provider may monitor the cysts. They’ll discuss treatment options if there’s concern that it could become cancerous.

How doctors diagnose chocolate cysts

A pelvic exam and imaging tests can help diagnose an ovarian endometrioma. If the cyst is large, your provider may be able to feel it during a pelvic exam. A transvaginal ultrasound or MRI can help show the size and location of the cyst.

Sometimes, surgeons remove the cyst and send the tissue to a lab to confirm the diagnosis.

How is it treated?

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

• Monitoring: You and your provider may monitor your cysts if they’re small and not causing symptoms.
• Surgery: Your provider may recommend surgery to remove painful cysts, growing or bigger than 4 centimeters. This improves your symptoms and reduces complication risks like rupture or infertility.
• Medications: Your provider may recommend medicine to help balance hormones and manage symptoms. This usually involves hormonal birth control.

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 option for you.

Should you remove an endometrioma?

You don’t always have to remove an endometrioma. Small cysts that don’t cause pain may not need treatment.

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 do an exam and order tests to see if an ovarian endometrioma is the source of your painful symptoms.

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

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

What can I expect if I have this condition?

Having ovarian endometriomas may be a sign of moderate to severe endometriosis. Your healthcare provider can work with you to help manage symptoms. They can also answer questions about fertility if you’re trying to get pregnant.

Can I get pregnant with endometrioma?

Yes, you can. It may be more difficult depending on the size of the endometrioma or if it affects both ovaries. Your healthcare provider can give you more information based on your situation.

Can ovarian endometriomas grow back?

Yes, they can come back after treatment. The risk depends on the size of the cyst, your age and the type of treatment.