Chronic lymphocytic leukemia complicated by plasmacytoma originating from different clones

In a woman with chronic lymphocytic leukemia (CLL), a plasmacytoma developed on the back region after four years. CLL cases complicated with plasmacytoma are rare. In the present case, the plasmacytoma showed kappa cytoplasmic immunoglobulin (Ig), and the CLL showed gamma lambda surface Ig. To reveal the clonal origin of CLL and plasmacytoma, we analyzed Ig gene rearrangements in the patient's peripheral blood and plasmacytoma. Ig gene DNA analysis confirmed the presence of different rearrangements in the heavy and light chain genes of CLL and plasmacytoma. These findings suggest that in this patient, the two B cell malignancies arose from expansion of two phenotypically and genotypically distinct clones.