[A case of isolated polyarteritis nodosa appeared in bilateral epididymides with asynchronous onset].

A 78-year-old man visited a hospital with a complaint of painful and swelling scrotums for 7 months. Although left epididymitis was suspected, antibiotic and non-steroidal anti-inflammatory drugs (NSAIDs) had no effects. After visit to our department, we performed left orchiectomy for the diagnosis and pain control. Pathological examinations showed necrotizing vasculitis in the epididymis, so he was diagnosed as polyarteritis nodosa (PN) in the left epididymis. He had no systemic symptoms, which made the diagnosis of isolated PN. One and a half years after operation, he felt the same pain in the right scrotum. We performed right orchiectomy. Pathological findings showed necrotizing vasculitis in the epididymis. Blood examinations revealed negative for myeloperoxidase anti-neutrophil cytoplasmic antibody (ANCA) and proteinase 3-ANCA, and computed tomography revealed that other organs were not involved. One year later, he had no recurrence.