Byeong Seok Kim, Young Woo Son, Seoung Jin Lee, Si Hyong Jang, Yong Wook Park, Young Ha Oh, Hong Yong Choi, Hong Sang Moon From the Departments of Urology and Pathology, College of Medicine, Hanyang University, Seoul, Korea Schwannoma is a tumor that arises from neural sheath Schwann cells of peripheral nerves. Schwannoma is mostly solitary, except when it occurs in association with Von Recklinghausen's disease. Solitary schwannoma can occur in association with a nerve anywhere within the body, but rarely occurs in the pelvis. Microscopically, the tumors can be divided into hypercellular bundles of spindle-shaped cells (Antoni A area) and areas of lower cellularity, with loose myxomatous arrangement of cells and fibers (Antoni B area). Complete resection of pelvic schwannoma is a curative treatment. We report a case of benign presacral cystic schwannoma that caused recurrent acute urinary retention in a 79-year-old woman, along with a review of the literature. (Korean J Urol 2007;48: 663-666)