ABSTRACT
Although the association between vasculitis and malignancy is rare, a multitude of combinations of vasculitis and malignancies have been reported. Only a few qualify as true paraneoplastic manifestations. In order to be considered as a paraneoplastic syndrome, several criteria should be met. They include: temporal relationship, concordance, consistency, rarity, and unexpected frequency of association between the two conditions (1,2). Temporal relationship is met when both conditions start at about the same time; concordance when both conditions follow a parallel course; and consistency when a defined vasculitis is related to a specific malignancy. These paraneoplastic syndromes are often uncommon but their co-occurrence is unexpectedly frequent. The only associations that satisfy these criteria and that we would recognize as truly paraneoplastic are (I) hairy cell leukemia with small-and medium-sized-vessel systemic necrotizing vasculitis of the polyarteritis nodosa group (3,4), (2) pseudo-Raynaud's phenomenon and solid tumors, and (3) cryoglobulinemia type I or II and hematological malignancies. Table 1 summarizes these paraneoplastic syndromes with their vasculitic component and their concurrent malignancies.
