An Endometriosis Patient’s Guide to Ovarian Cysts

Why endometriosis can cause ovarian cysts and the symptoms women need to watch for.

Medically reviewed in January 2021

The ovaries are small organs located on either side of the uterus, where eggs grow and mature. When a woman has endometriosis, endometrial tissue can attach to an ovary and form a type of ovarian cyst called an ovarian endometrioma. These cysts are pocket-like growths filled with fluid and tissue that adhere to the ovary. They are sometimes referred to as “chocolate cysts” because the contents, which include blood, tend to be brown and tarry and can have a similar color and texture to chocolate.

Endometriomas can cause a number of symptoms, including pain in the abdomen and pelvis. They can also damage the ovaries, which can interfere with fertility and make it difficult to conceive. They can also rupture, which will cause serious complications that require emergency medical treatment.

Below are a few things that endo patients should know about endometriomas and other types of cysts that can affect the ovaries. This article focuses on the types of cysts that typically affect women of childbearing age, the age group most often affected by endometriosis.

Types of ovarian cysts
In addition to ovarian endometriomas, there are other types of cysts that can affect the ovaries, all of which can cause symptoms and complications:

  • “Functional” cysts (also called “follicle cysts”). During ovulation, an egg develops inside a sac called a follicle. Normally the follicle will break open to release the egg, but sometimes it can remain intact, and a cyst can form as a result. This type usually resolves on its own and does not typically require treatment.
  • Dermoid Cysts. Also called teratomas, these type of cysts form from germ cells—cells capable of developing into different kinds of tissue, such as skin, hair, fat and teeth. In rare cases, they can become cancerous. They can adhere to the ovaries, but also to other organs.
  • Ovarian cystadenomas are tumors filled with watery fluid that develop on the outside surface of the ovary. They are benign in most cases, although a fraction of cases are cancerous. They can grow very large—some up to 12 inches in diameter—and cause a great deal of pain. Cystadenomas can also impact the liver.
  • Polycystic Ovarian Syndrome. Cysts can also form as a result of Polycystic Ovarian Syndrome (PCOS), a hormonal disorder associated with irregular periods, obesity, diabetes, hair growth, acne, infertility and other health issues. Though it is unusual, it is possible to have both endo and PCOS.

Diagnosing ovarian cysts
If a cyst is large, a healthcare provider may be able to feel it during a pelvic exam, and cysts may also be visible on an ultrasound. Determining the type of cyst will require blood testing. Depending on the size, the symptoms and the type, surgery may be needed to remove the cyst.

Symptoms to watch for
In most cases, cysts do not cause symptoms. However, ovarian endometriomas, other types of cysts, PCOS and endometriosis can all cause similar symptoms, which is why it is important to work with a healthcare provider to get an accurate diagnosis. Symptoms to watch for include:

  • Pelvic and low abdominal pain
  • Painful periods
  • Pain with sex
  • Pain with bowel movements
  • Fullness in the abdomen
  • Rectal or bladder pressure
  • Frequent urination
  • Unusual bleeding outside of menstruation
  • Unexplained weight gain

Ovarian cysts can cause ovarian torsion, which can cut off blood supply and damage or destroy the ovary. Cysts can also rupture. These complications require immediate medical treatment. Seek emergency care if you experience sudden, severe abdominal or pelvic pain, pain accompanied by fever or vomiting, or symptoms of shock, such as cold, clammy skin, rapid breathing, dizziness or weakness.

Featured Content


What are the Treatment Options for Endometriosis?

How hormonal contraceptives, surgery, and pain-relieving medications are used to treat endometriosis.

From Silent Suffering to Relief: Diagnosing Endometriosis

Learn how endometriosis is diagnosed, what to expect during your OB-GYN visits, and why women can go undiagnosed for years.

Everything a Gynecologist Wants You to Know About Endometriosis

Many women with endometriosis suffer in silence but treatment can ease their symptoms and help preserve their fertility.

What You Need to Know About Endometriosis

Severe period cramps and uncomfortable sex may be endometriosis red flags.

Endometriosis by the Numbers

Important facts and figures surrounding endometriosis.