ABSTRACT
Mature B-cell neoplasms most often show a single clone of cells, expressing only one class of immunoglobulin light chain. Identification of small B-cell clone or clonal population mixed with polytypic B-cells may be difficult. The identification of neoplastic cells relies on the comparison of the number of cells with positive and negative immunoglobulin expression. Despite predominance of large B-cells in the tissue section, analysis of lymphocytic gate for kappa and lambda expression shows only rare B-cells with suspicious cluster of kappa+ cells. However, in a subset of cases the phenotype of MCL is not typical and therefore it overlaps with that of CLL/SLL and other B-cell lymphoproliferations. Biclonal follicular lymphoma shows lambda clone with variable CD20 expression, and kappa clone with cohesive cluster of cells.
