Background: Endometriosis is a common gynecological disorder associated with pelvic pain and infertility. Endometriosis at cesarean section scar is an uncommon site of extrapelvic endometriosis. We report a case of endometriosis in cesarean section scar.Case Report: A case of 31-year-old woman who presented with a palpable mass and cyclic pain at the left lateral edge of the pfannenstiel incision scar. The skin of this edge had also become dark brown. She had previously undergone two cesarean sections. Physical examination revealed only a mild tenderness and a dark-brown mass at the left lateral edge of the scar. Transabdominal ultrasonogram demonstrated a hypoechoic mass with an irregular margin. Preoperative diagnosis was surgical scar endometriosis, surgical excision was performed and the tissue pathology confirmed the characteristic features of endometriosis. The postoperative course was uneventful, and no recurrence was found during the two-year follow-up period. Conclusions: Although cesarean section scar endometriosis is uncommon, the diagnosis should be considered in a woman presenting with a cyclically painful mass or nodule in the scar related to the menstrual period. Due to the increasing rate of cesarean sections, a large number of cesarean section scar endometriosis cases are found. Physicians should concern it, since it is a possible cause of post cesarean section scar-related masses. Surgical management remains the treatment of choice.

Keywords: cesarean section,, scar, Endometriosis, Surgery