Mesothelioma of the Tunica Vaginalis Testis Initially Treated as Hydrocele: A Case Report.

INTRODUCTION: Herein, we report a case of mesothelioma of the tunica vaginalis testis (MTVT), treated as a hydrocele. CASE PRESENTATION: A 65-year-old man was referred to our hospital after MTVT was incidentally diagnosed during hydrocelectomy performed for recurrent hydrocele. Left hemiscrotectomy was performed, and pathological examination revealed an epithelioid-type MTVT with invasion into the testis and spermatic cord. Immunohistochemistry was positive for D2-40 and calretinin, and negative for cytokeratin 5/6 and carcinoembryonic antigen. The patient remained disease-free for 12 months postoperatively without adjuvant treatment. CONCLUSION: MTVT should be considered in patients with long-standing or recurrent hydrocele. Wide surgical excision is essential for local control.