A giant peritoneal mesothelioma extending to the pelvic floor: A case report and review of the literature

Journal of Cancer Research and Therapeutics 2025 April 1 [Link]

Mathew Thomas, Harikrishnan Nandakumar, Parth Sampat, Stephen Graziano

Abstract

Malignant peritoneal mesothelioma (MPM) is a rare malignancy originating from the peritoneal serosa and is the second most common site of mesothelioma after the pleura. Localized disease presents as a focal circumscribed mass, whereas diffuse disease is usually associated with ascites and may metastasize to abdominal and pelvic lymph nodes. Cytoreductive surgery with heated intraperitoneal chemotherapy has been shown to improve progression-free survival and overall survival. Systemic chemotherapy with pemetrexed and platinum-based chemotherapy has also demonstrated a good treatment response. Recently, there has been an increased interest in the use of immune checkpoint inhibitors in the treatment of MPM. We present the case of a 59-year-old female with progressively worsening abdominal pain and constipation, who on further evaluation was found to have a huge MPM (17.3 × 17.1 × 13.3 cm) extending into the pelvic cavity with associated compression of the vagina, sigmoid colon, and ureters complicated by bilateral hydronephrosis. The tumor was deemed unresectable, and the patient was started on dual immunotherapy with ipilimumab and nivolumab. The patient had symptomatic improvement and a reduction in tumor size to 15.1 × 11 × 8.6 cm. Despite the initial response, the disease progressed (15.6 × 13.8 × 23.8 cm) and the patient ultimately succumbed to it. This case highlights the unique presentation of a massive localized MPM and emphasizes the need for further research to optimize treatment strategies.