An endometrioma is a type of ovarian cyst that contains endometriosis, a disease caused by endometrial-like cells growing outside the uterus. Endometriomas can be an indication of severe endometriosis. They can also cause acute and chronic pain, inflammation, and adhesions (abnormal connections between tissues) and negatively affect fertility.

What Is Endometriosis?

Endometriosis, also referred to simply as “endo,” is a painful chronic condition that affects more than 11 percent of U.S. women of childbearing age. Endometriosis is caused by the growth of endometrial-like cells in inappropriate locations. Normally, endometrial cells are found only in the endometrium, the lining of the uterus. With endometriosis, endometrial-like lesions commonly occur outside the uterus on the ovaries, fallopian tubes, and elsewhere in the pelvis and abdomen, including the bladder and intestines. Endometriosis can also be found in most other areas of the body.

Endometriosis lesions respond to estrogen. Symptoms initially occur with menstruation but can happen throughout the cycle.

Symptoms of Endometriosis

The symptoms of endometriosis can be severe and include chronic pelvic pain, bloating, and fertility problems. The cause of endometriosis is unclear but appears to be related to a combination of genetic and environmental factors. The primary risk factor is estrogen exposure. Endometriosis is associated with:

• Early onset of menstruation
• Late menopause
• High body-fat percentage
• Environmental exposure to certain chemicals

Diagnosis and Treatment of Endometriosis

Laparoscopic surgery is used to diagnose and treat endometriosis by identifying and removing lesions, a procedure known as excision. Several treatment options address pain and other symptoms by lowering estrogen levels using a variety of medications, including hormonal birth control. Anti-inflammatory drugs, opioids, acupuncture, and heating pads might also be used to reduce pain.

What Are Endometriomas?

Endometriomas are cysts containing endometriosis that form within the ovaries. Endometriomas are also referred to as ovarian endometriomas, deep ovarian endometriosis, and chocolate cysts. The term “chocolate cyst” describes the dark brown appearance of endometriomas caused by the collection of blood and shed endometrial tissue (similar to menstrual blood) trapped within the cyst.

Endometriomas cause an inflammatory response that leads to fibrosis (scarring) and adhesions and can affect fertility. The presence of endometriomas can indicate more severe and extensive endometriosis involving the pelvis and intestines. Endometriomas are associated with a twofold to threefold higher risk of some ovarian cancers.

Because endometrial tissue responds to estrogen, the endometrial tissue inside the cyst fluctuates during the menstrual cycle, growing and then shedding the way normal endometrium does. The cyst is encapsulated in scar tissue, so the trapped blood and shed endometrial cells build up within the cyst rather than leaving the body through menstruation.

This buildup can cause endometriomas to grow and sometimes rupture. Ruptured endometriomas are rare but can lead to serious medical complications, such as infections and internal bleeding, that may require immediate surgical treatment.

Endometrioma Signs and Symptoms

Endometriomas produce the same symptoms as endometriosis. Symptoms of endometriosis (and endometriomas) can increase and decrease, following the hormonal changes caused by the menstrual cycle. Symptoms tend to be worse immediately before menstruation and improve afterward.

Common symptoms seen with endometriomas include:

• Pain in the pelvis, abdomen, and back
• Heavy menstrual periods
• Painful menstrual periods (dysmenorrhea)
• Pain during sexual intercourse
• Pain during urination
• Pain during bowel movements
• Bloating
• Nausea and vomiting

When endometriomas rupture, they can also cause acute symptoms that include:

• Acute, severe abdominal or pelvic pain (usually on one side)
• Fever
• Nausea and vomiting
• Vaginal bleeding
• Systemic symptoms, including fever and dizziness

Endometrioma Diagnosis

If your health care provider suspects endometrioma, they’ll confirm diagnosis by taking a medical history and performing a physical exam (including a pelvic exam), as well as ordering blood tests, imaging studies, and ultimately, a surgical excision or biopsy.

Endometrioma Treatment

Treatment of endometriosis may include pain management, hormonal therapy, and cystectomy (surgical removal of the endometrioma). Hormonal therapies, including gonadotropin-releasing hormone antagonists such as elagolix (Orilissa), can reduce pain and the size of endometriomas but do not cause the cysts to go away. Managing endometriosis often requires surgery to remove endometrioma cysts and the adhesions they cause.

Surgery for Endometriomas

Because cysts occur within the ovaries, surgery can affect ovarian function and fertility. Surgery involving the ovaries can lead to ovarian failure and reduce the number of healthy eggs.

A woman’s desire to maintain fertility can affect decisions about the type of surgery performed to treat endometriomas. Conservative surgery may involve draining cysts and carefully removing the cyst capsule to help prevent recurrence while leaving the ovaries mostly intact. If maintaining fertility is not a priority, then more radical surgical approaches can be used. Hysterectomy and oophorectomy (removal of the uterus and ovaries) can be effective to prevent endometriomas but also cause irreversible infertility.

Endometrioma Complications

Endometriomas can have some serious and lasting complications due to adhesions, ruptured cysts, and effects on fertility.

Adhesions

Inflammation from endometriomas and endometriosis can cause painful scarring in the pelvis and abdomen. Adhesions occur when inflammation causes the peritoneum — the lining of the abdominal cavity and pelvic cavity — to form scars that bind organs together.

Serious complications can arise if adhesions affect the function of organs. Adhesions can result in dangerous intestinal blockages or prevent blood flow, leading to necrosis, or tissue death. Adhesions can also cause infertility by distorting the normal anatomy of the uterus, fallopian tubes, and ovaries.

Surgery is the only treatment for adhesions but also can cause inflammation, sometimes leading to more adhesions.

Ruptured Cysts

Endometrioma cysts rarely rupture, but the consequences can be serious when they do. In addition to causing severe pain, ruptured cysts can result in internal bleeding, acute inflammation of the peritoneum, and infection. These conditions are potentially life-threatening.

Fertility

Endometriomas can affect fertility in several ways. Large cysts can increase the risk of ovarian torsion — twisting of the ovary that can cut off its blood supply, killing the ovary. Endometriomas can impair normal egg production and release or lead to ovarian failure.

Endometriomas can also affect fertility treatments, or assisted reproductive technology, such as in vitro fertilization (IVF). IVF involves using medications that cause eggs to mature in the ovaries for harvest later. These treatments can exacerbate endometriosis symptoms and cause increased pain and growth of endometriomas. The presence of endometriomas can also make egg harvest more difficult by distorting the ovary or causing adhesions.

Endometrioma Prognosis

Endometriomas affect as many as 44 percent of women with endometriosis, usually those who have more severe disease. The cysts can cause chronic pain, infertility, severe complications, and an increased risk of ovarian cancer. Endometriomas are treatable but also frequently recur after surgery. Data regarding endometriomas is limited, so the prognosis (outlook) for women affected by endometriomas is not clear.

Endometrioma Risk Factors

Researchers have not yet identified risk factors specifically for endometriomas, but some of the risk factors for endometriosis are within your control. Steps you can take to lower your estrogen levels and risk of endometriosis include:

• Getting regular exercise
• Lowering body fat
• Avoiding excessive alcohol and caffeine
• Using hormonal birth control

Forming healthy habits such as staying active and eating better might not help prevent endometriomas, but it will definitely have a positive impact on your health.

Talk With Others Who Understand

MyEndometriosisTeam is the social network for people with lymphoma and their loved ones. On MyEndometriosisTeam, more than 125,000 members come together to ask questions, give advice, and share their stories with others who understand life with endometriosis.

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