Vasculitides associated with malignancy.

Vasculitides associated with malignancies are infrequent. We can group this syndrome under three broad clinical categories: vasculitide-associated malignancies or true paraneoplastic syndrome, malignancies masquerading as vasculitides, and vasculitides masquerading as malignancies. Recent new etiopathogenic hypotheses are discussed: an immunologic dysregulation with either handling, production, or elimination of circulating immune complexes; an immunogenetic abnormality with autogenes and oncogenes with up- and/or downregulation of cell proliferation through abnormal apoptosis; and direct involvement of a virus such as human T cell lymphotropic virus type I or Epstein-Barr virus. An update on several recently reported associations between vasculitides and malignancies is presented.