Waldenström macroglobulinemia () is a type of cancer affecting two types of B cells: lymphoplasmacytoid cells and plasma cells. Both cell types are white blood cells. It is characterized by having high levels of a circulating antibody, immunoglobulin M (IgM), which is made and secreted by the cells involved in the disease. Waldenström macroglobulinemia is an "indolent lymphoma" (i.e., one that tends to grow and spread slowly) and a type of lymphoproliferative disease which shares clinical characteristics with the indolent non-Hodgkin lymphomas. It is commonly classified as a form of plasma cell dyscrasia, similar to other plasma cell dyscrasias that, for example, lead to multiple myeloma. Waldenström macroglobulinemia is commonly preceded by two clinically asymptomatic but progressively more pre-malignant phases, IgM monoclonal gammopathy of undetermined significance and smoldering Waldenström macroglobulinemia. The Waldenström macroglobulinemia spectrum of dysplasias differs from other spectrums of plasma cell dyscrasias in that it involves not only aberrant plasma cells but also aberrant lymphoplasmacytoid cells and that it involves IgM while other plasma dyscrasias involve other antibody isoforms.Waldenström macroglobulinemia  is a rare disease, with only about 1,500 cases per year in the United States. It occurs more frequently in older adults. While the disease is incurable, it is treatable. Because of its indolent nature, many patients are able to lead active lives, and when treatment is required, may experience years of symptom-free remission. Signs and symptoms
Signs and symptoms of Waldenström macroglobulinemia include weakness, fatigue, weight loss, and chronic oozing of blood from the nose and gums.
The new World Health Organization (WHO) classification, however, places Waldenström macroglobulinemia under the category of lymphoplasmacytic lymphomas, itself a subcategory of the indolent (low-grade) non-Hodgkin lymphomas. Since the 1990s, there have been significant advances in the understanding and treatment of Waldenström macroglobulinemia. See also
List of hematologic conditions
Waldenström hyperglobulinemic purpura


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