We report a patient with an epidermotropic cutaneous T-cell lymphoma which transformed into an anaplastic cutaneous CD30+ T-cell lymphoma. Repeated relapses required prolonged systemic PUVA therapy. Two years after diagnosis, the patient had several episodes of infections of the respiratory tract. Serum electrophoresis now revealed significantly reduced polyclonal immunglobulin production and an additional band in the gamma fraction corresponding to IgG lambda monoclonal gammopathy. Thereafter, the patient suffered a pathologic fracture of the dorsolateral 5th rib on the right side and an accumulation of monoclonal plasma cells in the bone marrow confirmed the diagnosis of multiple myeloma (IgG lambda). Accordingly, 6 cycles of cytoreductive chemotherapy (alkeran, decortin) were given. After one year of steady state disease the patient lost weight and bone pain increased while only a few papular eruptions were detectable. Radiography showed multiple small osteolytic areas. A few months later he died with signs of bone marrow insufficiency.