Endometriosis - morphology, clinical presentations and molecular pathology

Endometriosis is found predominantly in women of childbearing age. The prevalence of endometriosis is difficult to determine accurately. Laparoscopy or surgery is required for the definitive diagnosis. The most common symptoms are dysmenorrhea, dyspareunia, and low back pain that worsen during menses. Endometriosis occurring shortly after menarche has been frequently reported. Endometriosis has been described in a few cases at the umbilicus, even without prior history of abdominal surgery. It has been described in various atypical sites such as the fallopian tubes, bowel, liver, thorax, and even in the extremities. The most commonly affected areas in decreasing order of frequency in the gastrointestinal tract are the recto-sigmoid colon, appendix, cecum, and distal ileum. The prevalence of appendiceal endometriosis is 2.8%. Malignant transformation is a well-described, although rare (<1% of cases), complication of endometriosis. Approximately 75% of these tumors arise from endometriosis of the ovary. Other less common sites include the rectovaginal septum, rectum, and sigmoid colon. Unopposed estrogens therapy may play a role in the development of such tumors. A more recent survey of 27 malignancies associated with endometriosis found that 17 (62%) were in the ovary, 3 (11%) in the vagina, 2 (7%) each in the fallopian tube or mesosalpinx, pelvic sidewall, and colon, and 1 (4%) in the parametrium. Two cases of cerebral endometriosis and a case of endometriosis presenting as a cystic mass in the cerebellar vermis has been described. Treatment for endometriosis can be expectant, medical, or surgical depending on the severity of symptoms and the patient's desire to maintain or restore fertility.