Endometriosis is (an often) painful and chronic gynecological disorder of the where tissue similar to that which normally grows in the lining of the uterus (endometrium), grows outside your uterus. The condition most commonly involves your ovaries, fallopian tubes and the tissue lining your pelvis, but in some cases can extend beyond these areas.
During a female menstrual cycle, endometrial tissue lining the uterus tissue builds up. If the woman does not fall preganant, this tissue lining is shed during her period/menses. However, in women with endometriosis, this endometrial tissue develops outside of the uterus, usually on other reproductive organs inside the pelvis or in the abdominal cavity. Each month, this misplaced tissue responds to the hormonal changes of the menstrual cycle – and builds up and breaking down (in the same way as endometrium), which then resulting in small bleeds inside of the pelvis, which will lead to inflammation, swelling and scarring of the surrounding normal tissue. When the ovary is involved, blood can be embedded within the normal ovarian tissue and form a blister of blood, which is surrounded by a fibrous cyst, called an endometrioma.