Iatrogenic myelomonocytic leukemia following melphalan treatment of scleromyxedema.

We report the case of a patient with scleromyxedema with abnormal monoclonal gamma globulin of the kappa type who was treated with melphalan (Alkeran), an alkylating agent. After nine and one-half years of therapy, the patient showed myelomonocytic leukemia. The risk of secondary malignancies must be considered when weighting the benefits and risks of melphalan treatment.