Concurrent development of "Burkitt-like" lymphoma and BCL-2-rearranged low-grade B cell lymphoma sharing the same germinal center origin.

B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma (BL) is a new entity in WHO classification 2008, and includes Burkitt-like transformation of follicular lymphoma (FL). However, the pathological significance of BCL-2/IgH translocation, which is characteristic in FL, in newly diagnosed cases of this disease is not well understood. We report a patient who developed B cell lymphoma with BL-like morphology on the shoulder, whose bone marrow was involved with FL-like cells. BL-like tumor cells harbored amplified c-MYC genes with BCL-2/IgH translocation, but FL-like cells solely had BCL-2/IgH translocation. The sequence analysis of the IgH gene revealed both of cells originated from the same clone, showing that the aggressive BL-like tumor originated from the FL-like clones simultaneously found in the bone marrow. This case suggests that the IgH/BCL-2 translocation found in newly diagnosed Burkitt-like lymphoma indicates a history of FL-like indolent lymphoma, even if such history is not documented.