Primary malignant mesothelioma of the tunica vaginalis of the testis. Immunohistochemistry and electron microscopy.

A case of primary malignant mesothelioma of the tunica vaginalis of the testis in a 75 year old man is here presented. Anamnesis for asbestos exposure was negative. Recurrent left hydrocele was the main symptom. Echography revealed a nodular mass in the caudal aspect of the epididymis and papillary projection on the surface of the tunica vaginalis of the testis. An inguinal left orchiectomy was performed. The tumor both in the solid area and in the papillary projections was identified as a malignant mesothelioma of epithelial type. The role of immunohistochemistry and ultrastructure for a correct definition of the tumor is underlined.