Translocation (18;22)(q21;q11) in B-cell lymphomas: a report of 4 cases and review of the literature.

Follicular lymphomas characteristically carry t(14;18)(q32;q21) which results in IGH-BCL-2 fusion. Variant translocations that juxtapose the BCL-2 gene with the immunoglobulin kappa (2p11) and lambda (22q11) light chain genes are rare. We report 4 cases of B-cell lymphoma/leukemia associated with t(18;22)(q21;q11). The t(18;22)(q21;q11) was the sole aberration identified by conventional cytogenetics in 2 cases. Three cases were classified as chronic lymphocytic leukemia, and one as follicular lymphoma based on morphology and immunophenotype. Fluorescence in situ hybridization analysis was performed on all 4 cases using a BCL-2 breakapart probe. The BCL-2 gene was rearranged in all cases. Immunoglobulin lambda light chain gene rearrangement was shown in 3 cases using bacterial artificial chromosome probes spanning the variable and constant clusters of the IGlambda gene. Each case was negative for MALT-1 rearrangement using a MALT-1 breakapart probe. These cases illustrate that t(18;22)(q21;q11) is more commonly observed in chronic lymphocytic leukemia and may represent either an initial or secondary genetic event.