Malignant transformation of abdominal wall endometriosis: a case report and literature review

Abdominal wall endometriosis (AWE) is a relatively rare subtype of endometriosis that has the potential for malignant transformation. It typically presents with nonspecific clinical symptoms, such as abdominal pain and palpable masses. Diagnosis primarily relies on multimodal imaging combined with histopathological examination. The main treatment strategies include carboplatin- and paclitaxel-based combination chemotherapy, resection of the abdominal wall mass, and hysterectomy with bilateral salpingo-oophorectomy. The uniqueness of this article lies in the patient experimentally receiving treatment with bevacizumab and sintilimab, while not undergoing hysterectomy with bilateral salpingo-oophorectomy.

This article presents the case of a 48-year-old G2P1 female, with no family history of gynecological cancer, who presented with a progressively enlarging abdominal mass over 1 month at her prior cesarean section scar site, two decades post-procedure. Computed tomography (CT) revealed multiple cystic hypodense lesions within the bilateral rectus abdominis muscles, measuring up to 11.03 cm × 7.64 cm. Her tumor markers were elevated [cancer antigen 125 (CA125): 98.6 U/mL; human epididymis protein 4 (HE4): 74.9 pmol/L]. Histopathological analysis confirmed malignant transformation of AWE into clear cell carcinoma. The patient underwent radical resection of a 15 cm × 15 cm infiltrative mass with 5 mm margins, followed by mesh hernioplasty and abdominal wall reconstruction. Postoperatively, the patient received 6 cycles of 21 days of chemotherapy comprising albumin-bound paclitaxel (300 mg), carboplatin (600 mg), bevacizumab (500 mg), and sintilimab (200 mg). However, pulmonary metastasis was detected 13 months after the completion of adjuvant chemotherapy.

This patient was not diagnosed with clear cell carcinoma of the abdominal wall prior to the initial surgery; therefore, hysterectomy and bilateral salpingo-oophorectomy were not performed. Our case highlights the need for increased vigilance toward malignant transformation of AWE, as well as may provide references for the treatment and follow-up of similar cases.