Background: Specific cutaneous lesions of Waldenström macroglobulinemia are rare and include neoplastic cell infiltrates, IgM bullous disease, and so-called IgM-storage papules, which characterize cutaneous macroglobulinosis (CM).
Observations: We report 2 patients with CM. In patient 1, CM started as small papules, as reported in most of the previously published case studies of CM. In patient 2, lesion evolution was remarkable by its severity, with large ulcerated nodules, and the disease progressed rapidly. As mentioned for half the previously described patients, peripheral neuropathy was suspected in patient 2 and demonstrated in patient 1, with production of antibodies to myelin-associated glycoprotein.
Conclusions: To the best of our knowledge, rituximab treatment of Waldenström macroglobulinemia associated with CM has not been described previously. Rituximab caused complete remission of the lesions in patient 1, whereas disease rapidly progressed in patient 2, and the patient died. These observations suggest that evolution of the cutaneous IgM-storage lesions reflects that of the underlying Waldenström macroglobulinemia, and CM is not a prognostic marker.