Chronic myeloid leukemia in Waldenström's macroglobulinemia.

Eighteen months after the occurrence of Waldenström's macroglobulinemia, Philadelphia (Ph1) chromosome-positive chronic myeloid leukemia developed in a 69-year-old woman. The coexistence of the two disorders was characterized by an initial reduction of paraproteinemia at the time that leukemia occurred, a long-lasting remission of the two disorders, and a final parallel increase of paraproteins and WBCs. Since leukemia occurred 15 months after the interruption of melphalan therapy, the potential mutagenic role of chemotherapy was considered irrelevant. Therefore, Waldenström's macroglobulinemia might favor the occurrence of chronic myeloid leukemia.