Case of hydrocele testis caused by vaginalitis, a rare manifestation of immunoglobulin G4-related disease.

We report an extremely rare manifestation of immunoglobulin G4-related disease, presented with hydrocele testis. A planned hydrocelectomy was converted to a high orchiectomy because of bloody fluid, suggestive of paratesticular malignancy. The histopathology showed vaginalitis, which was finally diagnosed as immunoglobulin G4-related disease. To the best of our knowledge, this is the first report of immunoglobulin G4-related disease representing hydrocele testis.