Endometriosis is a condition where there is normal endometrial cells (from the uterine lining tissue) found in other locations besides the uterine cavity. It is most commonly found to occur in the fallopian tubes, ovaries, tissue around the uterus, and other parts of the body (rare). This tissue is capable of responding to the normal hormonal (menstrual) cycle.
It is a common condition that is debilitating and poorly understood. The patient is often greatly affected not only by severe pain but also the possibility of the impact of disease on fertility. It is a disease that is commonly misdiagnosed as it has similar symptoms with fibromyalgia, interstitial cystitis, pelvic inflammatory disease, and irritable bowel syndrome.
Although the exact mechanism is still unclear, there have been various theories that have been proposed. The pathophysiology is most likely to be multifactorial. As previously mentioned, endometriosis occurs when endometrial (uterine lining) tissues are found in other parts of the body besides the uterus. It is most commonly located in the dependent portions such as the ovaries, tubes, uterosacral ligaments, posterior, and anterior cul-de-sac. These tissue then respond to the hormone cycle resulting in proliferation, secretion, and sloughing of the menstrual material. These material then cause inflammation and scarring resulting in pain, formation of adhesions, and distortion of anatomy.