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What Are Ovarian Cysts?

A cyst is usually a fluid-filled sac, like a small water balloon. These cysts are almost always harmless, and many go away on their own. No one knows exactly why cysts form. Usually they grow slowly, and they are rarely cancerous in women under 50. They can vary in size from as small as a pea to larger than a grapefruit. Many cause no symptoms at all. Often they are felt only during a pelvic exam.

Functional Cysts

Ovary with large cyst on surface.

Functional cysts are the most common kind of cyst found on an exam. One type, a corpus luteum cyst, is a normal part of reproduction. It forms after an egg is released. It needs no treatment and will go away on its own. Another type, a follicular cyst, forms when a follicle does not release a mature egg or continues to grow after releasing the egg. Functional cysts usually occur on only one ovary. They shrink on their own in 1 to 3 months.

Dermoid Cyst

Cross section of ovary with dermoid cyst.

Sometimes an unfertilized, early egg cell will start to grow into different kinds of tissue, such as skin, fat, hair, and teeth. This kind of cyst is called a dermoid cyst. Dermoid cysts can grow on one or both ovaries. Usually they cause no symptoms. But if they leak or become twisted, they can cause severe pain.

Endometrioma (“Chocolate” Cyst)

Ovary with large dark cyst on surface.

Sometimes tissue similar to the lining of the uterus (endometrium) grows and attaches to the outside of the ovary. This kind of cyst is often called a “chocolate” cyst because of its dark-brown color. These cysts can grow on one or both ovaries. They often cause pain, especially around menstruation or during sexual intercourse.

Benign Cystadenoma

Cross section of ovary with two cysts inside.

If the capsule that surrounds the ovary grows, it can form a cystadenoma. These cysts can grow on one or both ovaries. Usually they cause no symptoms. But if they become large, they can press on organs near the ovaries, causing pain. A cyst that pushes on the bladder can cause frequent urination. Sometimes these cysts rupture and bleed.

Author: StayWell Custom Communications
Last Annual Review Date: 5/15/2011
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