A case of Waldenström macroglobulinemia terminating in acute lymphoblastic leukemia

A case of acute lymphoblastic leukemia occurring in a patient with Waldenström macroglobulinemia more than 6 years after the onset of the disease is reported. At the time of acute transformation, bone marrow and peripheral blood lymphoid populations were almost entirely represented by lymphoblasts; the serum monoclonal peak had disappeared and no cells bearing surface or intracytoplasmic immunoglobulins were found. This observation suggests that the blast crisis might be derived from a dedifferentiative process within the lymphatic clone of the chronic phase.