Cutaneous Waldenstrom macroglobulinemia in transformation

Waldenstrom macroglobulinemia is a low-grade B-cell lymphoproliferative dis order of the elderly with characteristic monoclonal IgM-producing neoplasti c infiltrates of the bone marrow, lymph node, and spleen. Cutaneous manifes tations are usually nonspecific such as purpura, ulcers, and urticarial les ions. These lesions are caused by hyperviscosity of the blood, immune compl ex-mediated vascular damage, paraprotein deposition, and amyloid deposition . Specific skin lesions occur rarely and generally consist of translucent, flesh-colored papules composed of monoclonal IgM deposits. Rarely, there ma y be violaceous lesions composed of low-grade lymphoplasmacytic infiltrates characteristic of Waldenstrom macroglobulinemia. Both cutaneous manifestat ions of the disease, as well as disease transformation to high-grade, large cell lymphoma are rare. We report two very unusual cases of Waldenstrom ma croglobulinemia with documented skin disease that demonstrated transformati on to high-grade lymphoma. Both patients were elderly men with long-standin g Waldenstrom macroglobulinemia involving the bone marrow, who subsequently developed skin involvement by the disease. Waldenstrom macroglobulinemia c an rarely manifest as cutaneous disease, sometimes as a high-grade transfor mation of low-grade Waldenstrom macroglobulinemia elsewhere. Distinction of cases of transformed Waldenstrom macroglobulinemia from de novo cutaneous large cell lymphoma may be important, because the two entities are likely b iologically different.