Immunohistochemical Phenotyping of Plasma Cells in Lymphoplasmacytic Lymphoma/Waldenstrom's Macroglobulinemia is Comparable to Flow Cytometric Techniques

Lymphoplasmacytic lymphoma/Waldenstrom's macroglobulinemia (LPL/WM) can be difficult to distinguish from primary plasma cell neoplasms in bone marrow biopsies. Plasma cell immunophenotyping by flow cytometry can aid in this distinction as by this technique the plasma cells of LPL/WM express both CD19 and CD45 whereas primary plasma cell neoplasms are CD19 or CD45 negative. As immunophenotyping by flow cytometry has limitations, the comparative ability of immunohistochemistry to determine the plasma cell phenotype in WM/LPL was examined. The results indicate that immunohistochemistry yields results comparable to flow cytometry, and suggests that using both modalities in parallel compensates for the shortcomings of each.