<unk>  is the presence of endometrial tissue in and sometimes on the ovary. It is the most common form of endometriosis.<unk>  is found in 17–44% patients with endometriosis. More broadly, endometriosis is the presence of endometrial tissue located outside the uterus. The presence of endometriosis can result in the formation of scar tissue, adhesions and an inflammatory reaction. It usually is a benign growth. An<unk>  is most often found in the ovary. This ovarian endometriosis forms dark, fluid-filled cysts. These fluid-filled sacs can vary greatly in size and are known as<unk> s, also called "chocolate cysts". The fluid inside the cysts is thick, dark, old blood, giving it a chocolate-like appearance. It can also develop in the cul-de-sac (the space behind the uterus), the surface of the uterus, and between the vagina and rectum.
Endometrioma
Endometrioid tumor
Pelvic lipomatosis
Endometriosis
Endometrial stromal tumour
Corpus luteum cyst
Seminoma
Ovarian fibroma