Is clear cell sarcoma a malignant form of psammomatous melanotic schwannoma?

Abstract

The authors present a case of clear cell sarcoma (CCS) in which the tumor originated in the S-1 nerve root and had been previously diagnosed as psammomatous melanotic schwannoma (PMS). This is the third case of a spinal nerve root origin for CCS reported in the English-language literature. The similar histogenesis of CCS and malignant melanoma supports the hypothesis that biological agents or immunotherapy are potentially important areas of investigation. The patient underwent S1-3 laminectomy and gross-total resection of the mass lesion. The border of the resection was extended 1 cm distal to the tumor margin. The postoperative period was uneventful. The new histopathological diagnosis was CCS (malignant melanoma of soft tissue). Despite total resection, the patient returned with disseminated disease at the 18-month follow-up visit. His follow-up magnetic resonance image of the lumbar spine revealed sacral L5-S3 involvement of the vertebral bodies along with disseminated cauda equina seeding. A CCS originating from peripheral nerves is quite rare. The histopathological and immunohistochemical appearance of CCSs resembles those of PMSs. Surgery should be the first choice of treatment.