Expression of Wilms tumor-1 protein and CD 138 in malignant mesothelioma of the tunica vaginalis.

Malignant mesothelioma (MM) of the tunica vaginalis is a very rare tumor which can be difficult to diagnose histologically. We report an 83-year-old patient with MM of tunica vaginalis of the left testis. To the best of our knowledge, this is the first reported case of MM of the tunica vaginalis expressing Wilms tumor-1 protein, CD138, the expression of which could help in confirming the histopathological diagnosis and in targeting therapy.