Dermatofibrosarcoma protuberans (DFSP) is a rare, clinically challenging, soft tissue tumor. The main histologic differential of DFSP is usually a dermatofibroma. In 1990, the first report appeared demonstrating that cells of DFSP express the human progenitor antigen CD34 on their surface. Since then, there have been increasing reports of the usefulness of immunohistochemical staining with CD34 to differentiate DFSP from dermatofibroma and other soft tissue tumors. This literature is reviewed with special emphasis on the insights studies have provided into the histogenesis of DFSP. The literature demonstrating the practical applications of CD34 staining in the diagnosis and treatment of DFSP is also discussed.