Recurrent non-random balanced chromosomal translocation, usually involving the immunoglobulin heavy chain (IgH) gene or an immunoglobulin light chain gene and a proto-oncogene, which results in the overexpression of the latter under the control of an enhancer or promoter of the former, is a hallmark of many types of non-Hodgkin lymphoma (NHL) of B-cell origin. However, translocations between IgH and the immunoglobulin (Ig) light chain lambda gene (IgL), namely, a t(14;22)(q32;q11), have rarely been described in B-cell NHL. Herein we report the first case of marginal zone B-cell lymphoma harboring a t(14;22)(q32;q11) as its sole genetic abnormality in a patient with a 12-year history of systemic lupus erythematosus (SLE). Other interesting findings of this case include: 1) the neoplastic B-cells lack expression of both surface and cytoplasmic Ig light chain as revealed by flow cytometry and 2) monoclonal rearrangement of Ig light chain kappa (IgK) only due to k-deleting element (kde) recombination event. This case illustrates the necessity of utilizing a multi-modality approach in the diagnosis of B-cell NHL.
Keywords: K-deleting element; marginal zone B-cell lymphoma; systemic lupus erythematosus; t(14;22)(q32;q11).