Bilateral renal myxoid perineuriomas.

A perineurioma is a benign tumor of the peripheral nervous system which is composed of perineurial cells. Perineuriomas commonly develop as extraneural tumors from soft tissues and less commonly have intraneural localization. This case report describes a 25-year-old man with large bilateral renal masses that were diagnosed as perineuriomas. After surgical excision, the patient recovered fully and had no evidence of recurrence at the 1- and 2-year follow-up examinations.