Reported herein is a rare case of retroperitoneal schwannoma in a patient without von Recklinghausen's disease. This patient was free of symptoms, and the tumor
was found by chance during a periodical physical examination. Complete excision of the tumor was performed, and as of this writing, 36 months after the operation, the patient is free of the disease. In addition, a review was carried out on the 121 cases of retroperitoneal schwannoma reported in the Japanese literature from 1981 to 1992. In this series, malignant tumors were seen in 26.4% of all cases, and when this tumor was found in association with von Recklinghausen's disease, the malignancy rate increased to 52.9%. Thirty seven percent of the patients with malignant tumors had died at the time of writing of their case report, and their mean survival period was 18 months after the first surgical treatment. All the patients with benign tumors underwent complete resection and had a good prognosis