Waldenström macroglobulinemia

Abstract

Waldenström macroglobulinemia (WM) is a low-grade lymphoproliferative disorder characterized by the presence of an immunoglobulin M monoclonal protein in the blood and monoclonal small lymphocytes and lymphoplasmacytoid cells in the marrow. The disease is uncommon and there is a lack of clear diagnostic criteria. WM is treatable but not curable and long-term survival is possible. Therefore, the treating physician needs to carefully balance the risks and benefits of treatment. Treatments are aimed at relieving symptoms resulting from marrow infiltration and the hyperviscosity syndrome. Therapies available for initiation of treatment include alkylating agents, purine nucleoside analogs, and rituximab. Chlorambucil has been the mainstay of treatment for many years and remains useful, especially in older patients. Rituximab has become an important new therapy for this disease because of its positive treatment responses, acceptable toxicity, and lack of therapy-associated myelosuppression and myelodysplasia. Currently, rituximab is being combined with chemotherapy. Other options of treatment include interferon and corticosteroids. Emerging therapies include stem cell transplantation (autologous and allogeneic) for younger patients. Currently, there are few comparative data on which to state an absolute opinion concerning the best available treatment for patients with WM.

Figure 1

The differential diagnosis of WM from other B-lymphoproliferative disorders, such as B-CLL, mantle cell lymphoma, marginal zone lymphoma, follicular lymphoma, multiple myeloma, and amyloidosis. B-CLL—B-chronic lymphocytic leukemia; Cyto—cytochrome; Ig—immunoglobulin; WM—Waldenström macroglobulinemia.

Figure 2

The differential diagnosis of an IgM monoclonal protein includes malignant and benign causes. Malignant etiologies include WM, lymphoma, CLL, multiple myeloma, heavy chain disease, and amyloidosis. Benign etiologies include transient M proteins, monoclonal gammopathy of undetermined significance, cryoglobulins, and some immunodeficiency diseases. CLL—chronic lymphocytic leukemia; Ig—immunoglobulin; MGUS—monoclonal gammopathy of undetermined significance; WM—Waldenström macroglobulinemia.

Figure 3

Steps of diagnosis, differential diagnosis, prognosis, and treatment in patients with WM. CBC—complete blood count; Ig—immunoglobulin; MGUS—monoclonal gammopathy of undetermined significance; WM—Waldenström macroglobulinemia.