TO THE EDITOR: The co-expression of CD3 in B-cell lineage lymphomas or the aberrant co-expression of CD20 in T-cell lineage lymphomas has been rarely reported. We describe a 72-year-old female, who presented with systemic lymphadenopathy and a 2 cm-sized gastric mass. Biopsies of the lymph node and the gastric mass showed diffuse sheets of large, atypical lymphoid cells. The tumor cells were positive for B-cell antigens such as CD20 and CD79a as well as for the T-cell antigen CD3 and cytotoxic molecule TIA-1. In situ hybridization for Epstein-Barr virus-encoded RNA (EBER) showed positive signals in the nuclei of the majority of tumor cells. Molecular studies revealed rearrangements of the immunoglobulin heavy chain (IgH) region and the T-cell receptor (TCR)-γ genes, but not the TCR-β genes. The patient was treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), which resulted in near-total remission. This case illustrates the difficulty of lineage determination of non-Hodgkin lymphomas with only pan-B- and pan-T-cell markers. Unlike the previously reported cases, the present case showed molecular markers of both the B- and T-cell lineages, which further complicates the interpretation. The association of CD3-positive diffuse large B-cell lymphoma (DLBCL) with the Epstein-Barr virus (EBV) warrants further study.
Lymphoma diagnosis is based on histomorphology, immunophenotyping, flow cytometry, and molecular studies. Lymphomas are broadly classified as being of the B-cell and T-cell lineages, using immunohistochemistry and/or flow cytometry. Among the markers to determine B- and T-cell lineages, CD20 and CD3 are the most commonly used. T-cell lymphomas with aberrant expression of the B-cell marker CD20 or B-cell lymphomas with aberrant expression of T-cell associated antigens such as CD5, CD43, CD7, CD2, CD4, and CD8 have been reported [1-5]. However, cases of B-cell lymphoma with CD3 co-expression are extremely rare [6, 7]. Herein, we report a case of diffuse large B-cell lymphoma (DLBCL) in an elderly patient, with an aberrant co-expression of the T-cell associated antigen CD3 and cytotoxic molecule TIA-1, an infection with EBV, and a dual rearrangement of the immunoglobulin heavy chain (IgH) and T-cell receptor (TCR)-γ genes, but not the TCR-β gene.