This video displays what endometriosis involving the ovary looks like. It is often called a "chocolate cyst", named because of the characteristic consistency of the contents of the cyst. We think the "chocolate" forms as a result of breakdown of blood within the cyst which is usually present for a long time. These type of cysts are usually associated with the more severe forms of endometriosis and almost invariably exist with deposits of disease in other areas. They are a "marker" of bowel involvement.
Please note the disclaimer below in relation to these cysts.