Molecular Characterization of Testicular Mesothelioma and the Role of Asbestos as a Causative Factor

Abstract

Context.— Mesothelioma of the tunica vaginalis testis (TVT) is an extremely rare form of mesothelioma. Objective.— To compare the clinical and molecular characteristics of mesothelioma of the TVT with those of mesothelioma at other more common sites, including the relationship with exposure to asbestos. Design.— We present clinical and pathological data for 9 cases of primary TVT mesothelioma. We performed whole-genome sequencing on 3 cases for the first time. Results.— The majority (7 of 9 cases) of TVT mesotheliomas were epithelioid, with the remaining 2 cases showing biphasic morphology. Morphology and immunohistochemical profiles were indistinguishable from mesothelioma elsewhere. Asbestos exposure was documented for 7 of the 9 cases, with no information for 2 cases. The 3 TVT mesothelioma cases that underwent whole-genome sequencing displayed a mutational profile similar to that of mesothelioma at other sites, including NF2 and TP53 mutations. Conclusions.— The clinical and molecular profile of TVT mesothelioma is similar to that of mesothelioma elsewhere.