Clear cell sarcoma of tendons and aponeuroses: case presentation with special reference to immunohistochemical findings.

The case of a 27-year-old woman with recurring and metastasizing clear cell sarcoma (CCS) of tendons and aponeuroses is presented. Clinical setting, protracted course, and light microscopic appearance were in agreement with the original description. Immunohistologically, the tumor cells consistently expressed vimentin, S-100 protein, melanoma-associated antigens p97 and 7 kD peptide (as detected by monoclonal antibodies 96.5 and HMB-45, respectively), and major histocompatibility complex class I and (focally) class II antigens. Furthermore, the lymphocyte-associated antigen CD24 was detectable in the entire tumor cell population. Reactivity of the neoplastic cells with monoclonal antibodies to melanoma-associated antigens provides further evidence for a neural crest origin of CCS.