A case of peritoneal malignant mesothelioma following radiation therapy for cervical cancer

The present study presents a case of peritoneal malignant mesothelioma (PMM) following radiation therapy for cervical cancer. A 34-year-old Japanese woman, without asbestos exposure, was referred to the Department of Gynecologic Oncology, Saitama Medical University International Medical Center due to a cervical mass, and was diagnosed with cervical squamous cell carcinoma (SCC). The serum levels of tumor markers, including SCC antigen and cancer antigen 125 (CA125) were 229.0 ng/ml and 54.4 U/ml, respectively. The patient underwent concurrent chemoradiotherapy (CCRT), and a complete response was achieved. After 54 months, ascites was found at the rectouterine pouch, but peritoneal cytology suggested reactive mesothelial cell. After 62 months of CCRT, magnetic resonance imaging revealed masses in both the salpinges. The serum levels of SCC and CA125 were 0.9 ng/ml and 506.1 U/ml, respectively. Following this, left salpingectomy and peritoneal biopsy were performed laparoscopically. Histologic examination revealed atypical mesothelial cells with no continuity of background tubal epithelium. Immunohistochemistry showed positive staining for calretinin, thrombomodulin, mesothelin and glucose transporter 1. Based on these findings, the patient was diagnosed with PMM epithelioid type and underwent systemic chemotherapy; stable disease status has been obtained for 3 months. This case demonstrates the possibility of PMM occurrence within 10 years after radiotherapy, and indicates the importance of histological and immunohistochemical examination, particularly in cases of an atypical tumorigenesis pattern from the primary cancer.