The association of monoclonal paraproteinemia, neuropathy, and dermato-endocrine disturbances is well recognized in Japan, and it also occurs in white patients. Neuropathy in such patients is classically distal and sensorimotor, and the paraprotein almost always contains lambda light chains. A 58-year-old white man presented with severe progressive proximal motor neuropathy, dermato-endocrine changes, and an IgG kappa paraprotein. Over a 2 1/2-year period, treatment with melphalan and prednisolone produced improvement in the neuropathy and resolution of dermato-endocrine features with a corresponding decline in the serum paraprotein concentration. Subsequent reappearance of the paraprotein, despite treatment, was associated with clinical relapse.