Abdominal scar endometriosis, corresponding to the presence of an endometrial tissue near or inside an abdominal surgical incision, is a rare clinical event that can occur in women after gynecological or obstetric surgery. Generally, a triad consisting of underlying mass at the incision, cyclic menstrual scar pain, and history of previous gynecological or obstetric surgery leads to the preoperative diagnosis. In rare cases, the clinical presentation is atypical and the differential diagnosis with incarcerated incisional hernia, granuloma, abscess or other soft tissue tumors can be difficult. The authors describe the case of 39-year-old woman who underwent three previous cesarean sections, with a 20-week history of underlying palpable mass at the Pfannenstiel incision, associated to continuous pain. In this case, a surgical excision followed by the histology definitely clarified the diagnosis.