[Chronic urticaria-macroglobulinemia (Schnitzler syndrome): developing to IgM myeloma. Apropos of a case]

Schnitzler's syndrome has been described in 1972. It associates a chronic urticaria with leukocytoclastic vasculitis, a macroglobulinemia, bone pains, hyperostosis. In the twenty three cases reported, the evolution is benign but three patients including the princeps case developed a Waldenström's disease or a lymphoplasmocytic lymphoma. We present the case of one patient, aged 65, with Schnitzler's syndrome, who, after 6 years evolution, presents a IgM myeloma. Schnitzler's syndrome appeared as a pre-hemopathic state which has to be taken care of regularly and for a long time.