Malignant dermoid cysts are very rare. Dermoid cysts are not only found on the ovaries. They can also be found in children and in places other than the ovaries. Treatment for dermoid ovarian cysts often depends on the size. Often they are surgically removed if they happen to grow beyond 6 cm in diameter. The operation is usually performed as a laparotomy or by laparoscopy. Chocolate cyst (endometriom, endometioid cyst, endometrial cyst caused by endometriosis) caused by when a small amount of endometrial tissue begins to bleed, falls off the uterine wall and lodges inside the ovaries and begins to grow.