the small intestine, the large intestine, the uterus, and a bright red appendix with lines of pain

Could I Have Endometriosis On My Appendix?

Endometriosis is a condition in which tissue similar to the endometrial lining grows outside of the uterus. It often grows on nearby reproductive organs like the ovaries or fallopian tubes, but can also grow on other organs like the bladder. Sometimes it can even spread outside of the stomach or abdomen. In rare cases, endometriosis spreads to the appendix. This is known as appendiceal endometriosis.1

Knowing more about endometriosis on the appendix can help you potentially identify symptoms and seek medical assistance, if necessary.

Is endometriosis on the appendix common?

There is no precise data on how common endometriosis of the appendix is. Rates of endometriosis involving the appendix vary greatly, with numbers ranging from 1 to 22 percent.1

One study found that in women who choose to have their appendix removed during surgery for chronic pelvic pain or endometriosis, about 15 percent have evidence of endometriosis on their appendix. In women with confirmed endometriosis of the appendix, only 26 percent had an appendix that showed visible signs of endometriosis.2

According to our 2020 Endometriosis In America data, 25 percent of women have had endometriosis lesions that spread outside of the stomach/abdomen, with many reporting endometriosis lesions on the appendix.

What are the symptoms of endometriosis of the appendix?

Symptoms of endometriosis on the appendix can be very similar to the symptoms of acute appendicitis. These symptoms can include:1

  • Sudden pain in the lower right abdomen that gets worse with movement
  • Nausea and/or vomiting
  • Loss of appetite
  • Constipation or diarrhea
  • Fever
  • Abdominal bloating

Some people have no symptoms at all. For those who have symptoms, endometriosis of the appendix also tends to cause pain that coincides with the menstrual cycle.1

What causes endometriosis of the appendix?

The exact cause of endometriosis is unknown, and it is also unknown why it can spread to other organs or areas of the body. Researchers have a variety of theories, including retrograde menstruation, coelomic metaplasia theory, induction theory, and cellular immunity theory.1

How is endometriosis of the appendix diagnosed?

Because endometriosis of the appendix has symptoms so similar to appendicitis, it can be hard to diagnose. A physical exam is needed, and imaging tests like a CT scan can also help doctors make a diagnosis. Laparoscopic surgery and followed by testing of the endometriomas and scar tissue is the most precise way to diagnose endometriosis of the appendix.1

What is the treatment for endometriosis of the appendix?

Removing the appendix (an appendectomy) is the best way to treat endometriosis of the appendix. If the endometriosis is severe, removing the ileum (part of the small intestine) or part of the colon may be needed, depending on how the disease has spread.1

Things to consider

If you have symptoms of endometriosis of the appendix, talk with your doctor. Tell them about your symptoms and get an exam. If need be, ask for imaging tests to be ordered, especially if you have chronic pelvic pain. Although many people don’t think of the appendix as being involved with endometriosis, it can be affected, causing you pain and discomfort. There are ways to treat this and relieve your pain.

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