<unk>  ()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.<unk>  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.<unk>  is commonly preceded by two clinically asymptomatic but progressively more pre-malignant phases, IgM monoclonal gammopathy of undetermined significance and smoldering<unk> . The<unk>  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.<unk>  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.
Waldenström macroglobulinemia
Monoclonal gammopathy of undetermined significance
AL amyloidosis
Fibrin-associated diffuse large B-cell lymphoma
POEMS syndrome
Thymoma with immunodeficiency
Multiple myeloma
Diffuse large B-cell lymphoma