Malignant mesothelioma of the tunica vaginalis testis: a rare case and review of literature

BACKGROUND: Malignant mesothelioma of the tunica vaginalis is a rare tumour which comprises less than 1% of all mesotheliomas. CASE PRESENTATION: 69-years old patient with painful hard mass and hydrocele in the right scrotum to whom a right hydrocelectomy was performed. Any history of scrotal trauma or exposure to asbestos was not present. Excisional biopsy revealed a multinodular tumour with focal areas of necrosis and infiltrative growth. According to morphological and immunohistochemical findings, diagnosis of malignant biphasic mesothelioma of the tunica vaginalis testis was made. Two months after hydrocelectomy, right inguinal orchidectomy was performed. Post-surgical whole body CT scan revealed paraaortic and pararenal lymphadenopathy, likely to be metastatic. Adjuvant treatment with 6 cycles of cisplatin and pemetrexed was applied. After 3 cycles of chemotherapy, CT scan showed progression and the treatment was changed to gemcitabine 1 month after. CONCLUSIONS: Although malignant mesothelioma of the tunica vaginalis is a rare malignancy, it poses a diagnostic challenge which can mimic common inguinal or scrotal diseases such as hydrocele. Despite aggressive surgical procedures or adjuvant therapies, the prognosis remains poor.