Clear cell carcinoma arising from abdominal wall endometriosis—a report on two cases and literature review

BACKGROUND: Malignant transformation of abdominal wall endometriosis is extremely rare. Clear cell carcinoma and endometrioid carcinoma are the two most prevalent histological subtypes of malignant endometriosis. To date, approximately, thirty cases of clear cell carcinoma arising from abdominal wall endometriosis have been described worldwide. CASE PRESENTATION: We report two cases of clear cell carcinoma developing postoperatively in the anterior abdominal wall in women with a history of extensive endometriosis. Histopathology of the resected abdominal wall tumor demonstrated benign endometriosis contiguous with features of clear cell carcinoma. These histological features satisfied Sampson’s criteria which are required for diagnosing malignant endometriosis. Both patients were successfully managed with platinum-based adjuvant chemotherapy following cytoreductive surgery. CONCLUSION: Clear cell carcinoma arising from the abdominal wall endometriosis is a rare, highly aggressive cancer with a propensity to recur or metastasize. Due to the limited publications on this clinical entity, there are no clearly established protocols regarding adjuvant treatment, and an evaluation of prognostic factors is lacking. Clinicians must have a high index of suspicion for malignant endometriosis of the abdominal wall, particularly in patients with an abdominal wall mass, prior abdominal surgery, and long-standing endometriosis. By presenting our case, we expect to raise awareness and study of this rare endometriosis-related neoplasm.