Biclonal chronic lymphocytic leukemia: A study of two cases and review of literature

Chronic lymphocytic leukemia (CLL) is a common, immunophenotypically well-defined mature B-cell neoplasm. Demonstration of more than 5000/μL CD5+ B-cell population with co-expression of CD23, weak expression of CD20, and one type of immunoglobin light chain (either kappa or lambda) is necessary for the diagnosis of CLL. However, CLL with two populations of B-cells expressing both kappa as well as lambda (biclonal) light chains are extremely rare and has not been reported from India. We report two cases of biclonal CLL presented with leukocytosis, typical morphological features, and distinct immunophenotype of CLL. These cases are also an example which suggests that careful attention to the morphology of the blood smear and the entire immunophenotype panel is a must and will aid the proper diagnosis as only light chain ratios can be misguiding.