Tunica Vaginalis Mesothelioma

Mesotheliomas are uncommon tumours that occur in the pleura or peritoneum usually following asbestos exposure which may be of any duration and sometimes several years in the past. They are not related to smoking and those originating in the tunica vaginalis of testis are rare, representing less than 5% of all mesothelioma. The lung mesothelioma is the most popular. Trauma, herniorrhaphy and long term hydrocele are other possible predisposing factors. Other mesothelial lesions involving the paratesticular region include mesothelial cysts, reactive mesothelial hyperplasia, adenomatoid tumors, benign cystic mesothelioma, well-differentiated papillary mesothelioma.

Symptoms and Diagnosis

Mesotheliomas of the paratesticular region usually present as tumors with no specific findings, have a broad age of distribution making pre-operative diagnosis difficult. Although specific findings are not seen, but long lasting hydrocele has been reported as a predisposing factor. Ultrasound features show hydrocele which may be associated with well organized tissue fronds of mixed echogenicity; or multiple extratesticular nodular masses of increased echogenicity originating from the scrotal wall; or focal thickening of tunica vaginalis with nodularity; and lobulated mass lesions occupying the left epididymal head mimicking an epididymal tumor. Although mesotheliomas have been known to secrete markers calretinin, mesothelin, CAM 5.2, Alcian blue , Hale colloidal iron, vimentin, cytokeratin, calretinin, HBME-1 antigen, endothelial cell markers QBend-10 (CD 34), Factor VIII-related antigen (vWF) and UEA-1, panepithelial antibody (Lu-5) and membranous staining for BMA-120. The diagnosis may remain elusive on fine needle aspiration cytology in the pre-operative stage. The tumor has been found to be negative for CEA, Factor VIII related antigen, Ber-EP4, HEA-125 and blood group related antigens A, B and H. Reports for other markers such as Leu M1 and EMA remain conflicting and contradictory.

Treatment

Mesotheliomas are difficult to manage and no clear guidelines exist for management. Surgery has been suggested and orchidectomy is generally performed. Patients have been reported to have remained tumor free at 6 years following inguinal orchidectomy for limited tumor and at 2 years with lymph node metastasis.