Concomitant Presence of Two Distinct Clones of Chronic Lymphocytic Leukemia and Plasma Cell Myeloma in a Patient

A 74 years old male patient, presented with history of generalized weakness, fatigue, loss of appetite and breathlessness on exertion for past one and a half months. On examination, he was found to have significant pallor and generalized lymphadenopathy (cervical, axillary and inguinal). The skeletal survey showed punched out lytic lesions in skull and pelvic bones. The peripheral smear examination showed lymphocytosis with absolute lymphocyte count of 25,000/μL. The bone marrow aspirates revealed a hypercellular marrow with 74 % lymphocytes & 14 % plasma cells, suggestive of chronic lymphoplasmacytic disorder. The bone marrow biopsy had two morphologically distinct populations of lymphocytes & plasma cells. The immunohistochemical markers on bone marrow biopsy showed hat plasma cells were positive for CD138 with kappa light chain restriction. Flow cytometry showed B cell population with CD19/CD5 co expression, CD5/CD23 coexpression, were positive for CD22, CD20 and negative for FMC-7 and lambda light chain. In addition, plasma cells were also identified as CD45 negative cells and showed CD38/CD138 co-expression with variable CD19 and CD56 positivity. Serum protein electrophoresis revealed M band, serum immunofixation electrophoresis corresponded to IgA -Kappa. The final diagnosis of chronic lymphocytic leukemia with concomittant presence of plasma cell myeloma was concluded. This case imparts an important message to look for presence of coexisting entities in a single specimen and highlights the benefits of testing both plasma cell and B-cell compartments when the clinical features are not entirely consistent Flow cytometry together with protein electrophoresis can help to clinch difficult and rare dual diagnosis. These cases are rare and pose therapeutic challenge.