Rectus abdominis muscle endometriosis after cesarean section--case report.

Endometriosis is defined by the presence of functional endometrial tissue outside the uterus, where it is normally located. Endometriosis is one of the most common gynecologic entities affecting 8%-18% of menstrual women. Endometriosis can occur at intra- and extrapelvic localizations. The most common intrapelvic localizations are those involving the ovaries, Douglas' area, pelvic peritoneum, uterus, bladder and rectum. Abdominal endometriosis is the most common localization of extrapelvic endometriosis and usually develops in connective tissue. Extra-pelvic implantation of endometrial tissue may develop in any organ including the skin, lungs, liver, extremities, brain and stomach. Three years after cesarean section, a 35-year-old female was operated on for suspected anterior abdominal hernia at the site of previous section. An egg-sized tumor was removed from the rectus abdominis muscle and referred for histopathologic and immunohistochemical analyses. The results showed endometriosis of the muscle with positive estrogen and progesterone receptors. A year after the procedure, treatment with gonadotropin-releasing hormone analogs was continued due to recurrent pain in the scar area, along with ultrasonography and biochemical marker (carbohydrate antigen 125) follow-up. Clinical diagnosis of scar endometriosis can be made by thorough history and physical, ultrasonography and biochemical examinations. Scar endometriosis should always be considered when the symptoms occur in a cyclic and hormone-dependent pattern, mostly after gynecologic operations, and worsening during menstruation. Definitive diagnosis is based on histopathologic analysis.