Cutaneous macroglobulinosis deposits in a patient with IgM paraproteinemia/incipient Waldenström macroglobulinemia.

A 43-year-old healthy patient developed disseminated flat skin-colored to red-brown papules over a few months. These papules were the result of cutaneous IgM deposits representing the first symptom of a hitherto undiagnosed IgM paraproteinemia. This extremely rare skin manifestation of IgM paraproteinemia e. g. possibly incipient Waldenström macroglobulinemia should be included in the histopathological differential of eosinophilic dermal deposits.