Scar endometriosis as an easily misdiagnosed abdominal mass: a case report and review of the literature

Scar endometriosis, which is characterized by ectopic endometrial-like glands and stroma surrounding scar tissue, is rare and presents diagnostic challenges due to its inconsistent presentation. We report a case of a 40-year-old woman who had previously undergone two cesarean sections and a hysterectomy, in whom a mass in the subcutaneous layer of the lower abdomen was incidentally discovered by computed tomography (CT). A physical examination revealed a linear cesarean scar with a palpable, pigmented mass. An enhanced abdominal CT scan revealed an approximately 3.5-cm ill-defined soft tissue mass infiltrating the rectus abdominis muscle. A desmoid tumor was suspected based on the radiological findings, and endometriosis was also considered in light of the patient’s medical history. Wide mass excision was performed, ensuring 5-mm margins. The mass was completely excised, and a histopathological examination revealed endometriosis. Due to its rarity, scar endometriosis in the abdominal area can be easily misdiagnosed. Therefore, a heightened suspicion of scar endometriosis should be maintained in female patients with a history of abdominal or pelvic surgery presenting with an abdominal mass. Although imaging modalities can play a supportive role in the diagnosis, an extensive medical history assessment and comprehensive physical examination remain crucial.