Abdominal wall mass suspected of endometriosis: clinical and pathologic features.

Objective: To evaluate the clinical and pathological characteristics of lower anterior abdominal wall masses suspicious for endometriosis.

Methods: A retrospective review of 38 patients who underwent surgery for a lower anterior abdominal wall mass suspicious for endometriosis was performed. Those with skin and intraperitoneal masses, lipomas, hernias, and metastatic malignant masses were excluded. Patient age, body mass index, delivery history, dysmenorrhea, and mass size and location were analyzed.

Results: Thirty-seven (97.3%) patients had a relevant surgical history, including 35 (92.1%) with a history of cesarean section (C/S). Among the three patients with no history of C/S, 1 underwent total abdominal and another total laparoscopic hysterectomy, and 1 had no previous surgical history. The mean (±standard deviation) size of the abdominal masses was 3.2±1.2 cm. One patient developed a recurrent mass after excision of abdominal wall endometriosis. Trocar site endometrioma was found in one patient following total laparoscopic hysterectomy. According to the final pathology reports, endometriosis was found in 35 (92.1%) of patients. The remaining 3 patients (7.9%) had malignancy: adenocarcinoma, squamous cell carcinoma, and extra-gastrointestinal stromal tumor. Before surgery, only 3 patients (7.9%) underwent fine-needle aspiration biopsy of the masses, which were all postoperatively confirmed to be pathologically benign.

Conclusion: Although most abdominal wall masses in the present sample were endometriosis occurring at the scar site from a previous operation, 7.9% of patients ultimately exhibited malignancy. Therefore, all patients with suspected anterior wall endometriosis should undergo preoperative biopsy to identify the few that will have an alternative diagnosis.