Polyarteritis Nodosa Presenting with Bilateral Testicular Swelling and Complicated by Unilateral Facial Nerve Palsy

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that is generally restricted to medium-sized vessels. Here we describe the first case of a patient in which a bilateral testicular mass was a presenting symptom and the diagnosis was made on the basis of testicular histopathology. A 53-year-old Asian man presented with a history of constitutional symptoms and testicular swelling. Scrotal ultrasound revealed two avascular, bilateral, intratesticular lesions. The bilateral testicular abscess was treated without improvement. The patient developed left seventh cranial nerve palsy during his admission. The clinical changes made vasculitis or a related disorder more likely and the patient underwent a right testicular biopsy. Histopathology demonstrated features of transmural inflammation and fibrinoid necrosis of medium-sized vessel walls, consistent with PAN. This case illustrates the difficulty in diagnosing polyarteritis nodosa with isolated bilateral testicular swelling and the delay in the diagnosis. After 9 months of follow-up, no relapse had occurred and the patient's testosterone level was on the lower side of normal.