Burkitt lymphoma/leukaemia transformed from a precursor B cell: clinical and molecular aspects

ABSTRACT

Burkitt lymphoma ⁄ leukaemia (BL ⁄ L) is a heterogeneous disease with respect to epidemiological patternsand cell origin. The occurrence of BL⁄ L with an immature phenotype raises the question whether thisphenotype might be a consequence of early B-cell transformation or, alternatively, a secondary feature oftransformed, mature B cells. It also poses important clinical questions regarding diagnosis and therapeuticprocedures. Here we describe the case of a 4-yr-old child with BL ⁄ L and FAB L3 morphology, with phenotypicand genotypic characteristics of a CD10+ precursor B-cell acute lymphoid leukaemia (ALL) associatedwith t(8;14)(q24;q32). Molecular analysis showed expression of RAG1 and RAG2 and an unmutated VDJClimmunoglobulin rearrangement coinciding with a lack of AICDA expression, indicating an immature B-cellorigin. His clinical response suggested that FAB L3 ALL with MYC rearrangement and an aberrant precursorB-cell phenotype is clinically similar to BL ⁄ L. Moreover, short, intensive chemotherapeutic protocolsseemed to be beneficial. This case also allowed us to refine the description of cellular and molecularvariants of BL⁄ L regarding the cell origin and pathogenesis of this biologically heterogeneous disease.(AU)