Endometriosis. Endoscope view of endometriosis on an ovary (white, upper right). The endometriosis cyst is the small, dark purple rounded area on the ovary. Endometriosis is a condition where detached parts of the uterus's inner lining (endometrium) escape into the abdomen (via the Fallopian tubes) and attach themselves to internal organs. The lesions and cysts that result, bleed at the time of the menstrual cycle and cause great pain. The lesions and cysts vary in appearance from red to white, clear and black. Treatment is usually with drugs. This ovary's Fallopian tube is at upper left, held by the metal probe. A ligament (white, lower left) attaches the ovary to the uterus.