Malignant mesothelioma of tunica vaginalis testis: Report of a very rare case with review of the literature

Introduction: Mesothelioma of the tunica vaginalis testis is a extremely rare tumor and represents 0.3 to 0.5% of all malignant mesotheliomas. Exposure to asbestos often precedes illness. Because of its low incidence and nonspecific clinical presentation, it is mostly diagnosed accidentally during surgery for other reasons and the prognosis is usually poor. We present a case of a patient with a mesothelioma of tunica vaginalis testis, diagnosed secondarily during hydrocele surgery, with long-term survival after radical surgery.
Materials and methods: a 40 years old patient was admitted to our department for routine surgery of a left hydrocele. During the operation a frozen section analysis was requested because of the unusual nodular thickening of the tunica vaginalis: the examination revealed a diffuse malignant mesothelioma with epithelioid structure and tubular-papillary proliferation. Therefore a left hemi-scrotectomy with left inguinal lymph node dissection was performed.
Results: The definitive histology confirmed the previous report of diffuse malignant mesothelioma with angio-invasion but normal testicle findings and negative lymph nodes. No metastases were found on the CT-scan. For the first 2 years a CT was repeated every 4 months, for other 3 years every 6 months and then yearly. Six years after surgery the patient is classified as no evidence of disease.
Conclusions: malignant mesothelioma of the tunica vaginalis testis is a rare entity, often initially thought to be a hydrocele or an epididymal cyst. An aggressive approach with hemiscrotectomy with or without inguinal and retroperitoneal lymphadenectomy can reduce the risk of recurrence.