BCL6 and diffuse large B-cell lymphoma: The majority of components of CL were clonally related, suggesting a common origin.4,5 In fact, the definition of CL is a matter of debate because it is difficult to prove simultaneous occurrence of two unrelated lymphomas and that CL is not just a clonal evolution such as histologic transformation (eg. FL or CLL to DLBCL).3,6 In our case, aside the different morphologies in two components, the FISH analysis of the mantle cell component was negative for rearrangement of the BCL6, MYC, or BCL2 genes and the Burkitt component was negative for the BCL6, BCL2, and CCND1/IGH rearrangements.