This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Plasmacytoid lymphomas may be associated with an increase in 
Select and explain. 
A. IgG, B. IgM, C. IgA, D. IgE
B: IgM
Answer: B: IgM 
Explanation: *Lymphoplasmacytic lymphomas are otherwise called as plasmacytoid lymphomas or immunocytomas. *It is a mature B cell neoplasm of older adults (60-70years)*Bone marrow shows small lymphoid cells and admixed plasma cells*These plasma cells secrete monoclonal IgM*IgM can cause a hyperviscosity syndrome called Waldenstrom&;s macroglobulinemia.(Ref: Robbins 8/e p612)