It is now recognized that most neoplasms diagnosed previously as inflammatory malignant fibrous histiocytomas represent DDLPS with these tumors showing 12q13–15 amplifications or gains, as well as immunohistochemical expression of MDM2 and usually CDK4, and amplification of MDM2 and CDK4 with FISH analysis. This evidence concerns the gene MDM2 and undifferentiated pleomorphic sarcoma, inflammatory variant.