Prognostic value of high serum levels of CA‐125 in malignant secretory peritoneal mesotheliomas affecting young women. A case report with differential diagnosis and review of the literature

AIMS: Very few cases of diffuse, malignant, peritoneal mesothelioma have been reported in young women. Distinction between peritoneal mesothelioma and serous epithelial tumours, including papillary serous carcinomas and borderline serous tumours, can be difficult. Differential diagnosis based on clinical appearance and imaging techniques is broad and inconclusive, thus the diagnosis must be confirmed by histological examination. Because the vast majority of tumours involving the peritoneal and serosal surfaces are due to primary or metastatic serous epithelial tumours, there is a tendency on part of pathologists to disregard the possibility of mesothelioma when examining a biopsy or excision specimen. This is especially likely to occur when mesothelioma is associated with highly elevated serum levels of CA-125, which is the typical tumoral marker of epithelial serous tumours from the ovary. The association between peritoneal mesothelioma and high serum levels of CA-125 has been reported in the literature only in two cases. CASE DETAILS: In order to avoid a misdiagnosis of this neoplasm we describe a new case of peritoneal mesothelioma in an 18-year-old woman with high serum levels of CA-125. CONCLUSIONS: Besides its clinicopathological characteristics and its histological, immunohistochemical and ultrastructural features, we describe its biological behaviour, which seems to be worst when CA-125 levels are high.