Angiogenesis and osteopontin expression in paraskeletal myeloma with plasmablastic morphology and aggressive clinical course: a report of two cases

Extramedullary disease (EMD) of multiple myeloma (MM) can present as paraskeletal (paraosseous) plasmocytoma (PP) that arise from skeletal focal lesions or extramedullary plasmacytomas (EMP) that derive from hematogenous spread. The pathogenetic mechanisms that distinguish classical MM, PP, and EMP are still insufficiently known, as are the therapies that would be effective in EMD. The aim of this study was to evaluate immunohistochemically the angiogenesis, determined as microvessel density (MVD) and osteopontin expression in PP, of two patients with MM of plasmablastic morphology and an aggressive course of disease. We found high levels of MVD and osteopontin expression in both cases of PP. The role of angiogenesis and osteopontin in EMD should be clarified in future investigations, especially since there are no satisfactory therapeutic protocols for this form of multiple myeloma, and both of these biological factors can be the potential targets of new therapies.