Differentials
Multiple myeloma (MM)
SIGNS / SYMPTOMS
Bone pain related to lytic bone lesions is frequent in MM though hyperviscosity syndrome is uncommon.
Splenomegaly and hepatomegaly are not a feature in MM.
INVESTIGATIONS
Serum protein electrophoresis with immunofixation typically reveals IgG or IgA monoclonal protein. IgM MM is very rare.
Bone marrow biopsy reveals an infiltrate of clonal plasma cells that are morphologically different to lymphoplasmacytic cells of WM.
Flow cytometry and immunohistochemistry reveals tumor cell surface markers specific for MM (e.g., CD5-, CD10-, CD20-, CD138+, sIg-).
CT scan frequently reveals lytic bone lesions, which are usually absent in WM.
Low-grade B-cell lymphomas (e.g., follicular lymphoma)
SIGNS / SYMPTOMS
No specific signs or symptoms differentiate low-grade B-cell lymphomas from WM.
INVESTIGATIONS
Lymph node excisional biopsy reveals morphologic appearance suggestive of follicular lymphoma (i.e., follicles, small lymphocytes: centrocytes and centroblasts).
Bone marrow biopsy reveals infiltrate of small lymphocytes that are morphologically different to lymphoplasmacytic cells of WM.
Flow cytometry and immunohistochemistry reveals tumor cell surface markers specific for low-grade B-cell lymphoma (e.g., CD5-, CD10+).
Chronic lymphocytic leukemia (CLL)
SIGNS / SYMPTOMS
No specific signs or symptoms differentiate this condition from WM.
INVESTIGATIONS
Serum protein electrophoresis with immunofixation may or may not reveal IgM monoclonal protein.
Flow cytometry and immunohistochemistry reveals tumor cell surface markers specific for CLL (e.g., CD5+, CD20 dim, CD23+).
Marginal zone lymphoma (MZL)
SIGNS / SYMPTOMS
No specific signs or symptoms differentiate this condition from WM.
INVESTIGATIONS
Serum protein electrophoresis with immunofixation may or may not reveal IgM monoclonal protein.
Flow cytometry and immunohistochemistry reveals tumor cell surface markers specific for MZL (e.g., CD5-, CD10-).
Monoclonal gammopathy of undetermined significance (MGUS)
SIGNS / SYMPTOMS
Absence of symptoms. MGUS is an asymptomatic condition.
INVESTIGATIONS
Blood test shows normal CBC.
Serum protein electrophoresis with immunofixation reveals monoclonal protein <30 g/L.
Bone marrow biopsy reveals infiltrate of clonal plasma cells <10%.
Primary cold agglutinin disease
SIGNS / SYMPTOMS
No symptoms and signs related to lymphoma, such as lymphadenopathy and splenomegaly.
INVESTIGATIONS
Imaging shows no radiologic evidence of lymphoma such as lymphadenopathy or splenomegaly.
Blood testing shows evidence of hemolysis. In addition, direct antiglobulin test (DAT) is positive for anti-C3d; cold agglutinin titer is 1:64 or larger.
Bone marrow biopsy: no evidence of lymphoma.[51]
Use of this content is subject to our disclaimer