Immunoflow cytometry compared with PCR for the identification of clonality in FNAs of T-cell-rich B-cell lymphomas

The study aimed to compare the utility of immunoflow cytometry (IFC) with two IgH polymerase chain reaction (PCR) methods for the identification of clonality in fine needle aspirations (FNAs) from T-cell-rich B-cell lymphomas (TCRBCLs).

Ten cases of TCRBCLs were identified in which IFC had been performed according to our previously described method. Seven of these were cases in which the original diagnosis had been made by FNA cytology with IFC and cell block immunohistochemistry (IHC). The remaining three cases only had biopsies with histology, IFC and IHC. Formalin-fixed paraffin-embedded FNA cell block or histology tissue from these specimens had also been submitted for IgH PCR clonality studies using primers FR2a/VLJH and primers FR3a/VLJH. The results were reviewed and compared.

All 10 case demonstrated B-cell clonality for at least one of the primer sets on PCR, but none showed light chain restriction on IFC. All TCRBCLs were positive for CD20 and CD79a but negative for CD10 and BCl-2. They were also consistently negative for CD22, CD23, CD5, CD43, ALK-1, cyclin D1 and CD30.

If IgH PCR clonality assays had a turnaround time of 1 or 2 days, there might be a strong case for these studies supporting or even replacing IFC, in the FNA diagnosis of lymphoid lesions.