Atypical Burkitt lymphoma arising from follicular lymphoma: demonstration by polymerase chain reaction following laser capture microdissection and by fluorescence in situ hybridization on paraffin-embedded tissue sections.

A 77-year-old man with disseminated lymphadenopathy was referred to our hospital. An inguinal lymph node biopsy specimen had the appearance of composite lymphoma consisting of follicular lymphoma and atypical Burkitt lymphoma. The bone marrow was involved, and chromosomal analysis of the marrow showed t(8;14) and t(14;18) in identical cells. The patient underwent systemic chemotherapy but died of lymphoma 4 months later. Polymerase chain reactions performed on cells obtained from follicular and diffuse components by laser capture microdissection showed the two components to be clonally identical. Moreover, fluorescence in situ hybridization performed on paraffin-embedded tissue sections demonstrated an immunoglobulin heavy chain (IGH)/BCL2 translocation signal in both follicular and diffuse components, but an IGH/c-MYC translocation signal in only the diffuse component. Accordingly, the atypical Burkitt lymphoma arose from the follicular lymphoma as a consequence of the additional IGH/c-MYC translocation, then involving the bone marrow.