Multicystic malignant mesothelioma of the tunica vaginalis with an unusually indolent clinical course.

We report an extremely rare case of a multicystic malignant mesothelioma in the tunica vaginalis with an unusually indolent clinical course. A 48-year-old man presented with a one-month history of painless swelling of right scrotal contents. Ultrasonography and computed tomography (CT) revealed a multicystic mass in the right scrotal sac with evidence of neither distant nor lymph node metastases. The testicular tumor markers were within the normal limits. Inguinal orchiectomy was performed under the suspicion of a malignant tumor. The cystic tumor consisted of fibrocellular, microcystic and adenomatoid elements microscopically was diagnosed biphasic malignant mesothelioma of tunica vaginalis but no invasion into the testis, epididymis and also scrotum. The patient has been disease-free for 72 months and is being followed on an outpatient basis with no further adjuvant therapy.