Endosialin expression was also present in almost 80% of fibrosarcomas/ spindle cell sarcomas not otherwise specified in this study; these are a group of spindle cell neoplasms with fascicular or ‘herringbone' architecture and which also lack a specific immunophenotype, again supporting the possibility that endosialin might be an indicator of both ‘mesenchymal' differentiation and lack of differentiation. Here, CD248 is linked to fibrosarcoma.