Rearrangement of the beta T-cell receptor gene in a monocytoid B-cell lymphoma.

We describe an unusual case of monocytoid lymphoma displaying a rearrangement of the T-cell receptor beta-chain gene associated with a rearrangement of the immunoglobulin heavy-chain gene, and of the lambda light-chain gene. This lymphoma was morphologically similar to previous cases in the literature, and was clinically of low grade. The lymphoma expressed the lambda light chain, HLA-DR, CD21, and CD22. Though the B-cell lineage of this lymphoma seems very likely, the genotypic profile raises a cautionary note regarding the supposed high stage of differentiation of monocytoid lymphomas.