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 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.

Florid Mesothelial Hyperplasia Associated with Abdominal Wall Endometriosis Mimicking Invasive Carcinoma

Florid mesothelial hyperplasia typically occurs in the pelvis, abdomen, or chest associated with an underlying neoplastic or inflammatory process. These lesions are of clinical significance because they can mimic a neoplasm. Early reports were published in the 1970s, but only a few case series of such lesions have been published in the gynecologic pathology literature. Here, we report a case of florid mesothelial hyperplasia with an infiltrative growth pattern, mimicking an invasive carcinoma. The lesion was associated with endometriosis forming a mass lesion in the abdominal wall. Histologically, tubular arrangements and nests of mesothelial cells, some with artifactual slit-like spaces, formed a stellate lesion adjacent to endometrial glands and stroma. Cytologic atypia was mild and reactive, and positive immunostaining for calretinin, WT-1, and cytokeratin 5 identified the lesion as mesothelial and benign. We describe in detail the histologic findings in this case and review the pertinent literature. We discuss the clinically importance of this diagnostic pitfall and the path to arriving at the correct diagnosis.

A Comparison of The Clinical Characteristics Comprising Abdominal Wall Endometriosis of Various Types

Purpose To classify abdominal wall endometriosis (AWE) according to the invasive levels of tissue mass, and to compare the differences in clinical characteristics between different types of AWE. Methods In this study, we retrospectively analyzed the clinical data of 367 patients who had undergone resection of abdominal-wall endometriotic lesions at the Peking Union Medical College Hospital from January 2008 to December 2018, and we divided the patients into three types according to their deepest level of lesion invasion. Type I designated invasion of skin and subcutaneous tissue; type II, of fascia and rectus abdominis; and type III, of peritoneum. We classified, compared, and analyzed the general conditions, clinical manifestations, auxiliary examinations, surgical conditions, postoperative conditions, and recurrence status of patients. Result s Of the 367 patients, type I patients accounted for 13.62%, type II patients for 56.68%, and type III for 29.7%. With respect to group comparisons, we observed that as the location of the mass deepened, the rate of concurrent pelvic endometriosis increased (P = 0.007), recurrent AWE was augmented (P = 0.02), the size of the mass increased (P < 0.001), the rate of multiple lesions became elevated (P < 0.001), the rate of mesh implantation increased (P < 0.001), the length of postoperative hospital stay (P < 0.001) was lengthened, the number of postoperative fever cases (P = 0.006) increased, and the risk of drainage placement (P < 0.001) was enhanced. The 5-year cumulative recurrence rate was 3.3%, and there was no significant difference in the recurrence rate among various types of AWE. Conclusion Various types of AWE manifest different clinical characteristics, surgical options, associations with pelvic endometriosis, and postoperative conditions.