2003 Volume 43 Issue 2 Pages 71-76
We present morphologic, immunohistochemical and molecular profiles of signet ring cell lymphoma (SRCL). The lymph node removed showed a diffuse infiltration of lymphoma cells consisting of large blastic cells (LBC)and signet ring cells (SRC). LBC had a large oval-shaped nucleus, occasionally with one or more nucleoli and scant cytoplasm, while SRC possessed eosinophilic cytoplasmic inclusions (Russell bodies) that displaced and distended the nucleus. LBC were CD20+, CD79a+, CD138- and CD10-. SRC were CD20-, CD79a+, CD138+ and CD10-. Both LBC and SRC contained the same monoclonal cytoplasmic immunoglobulin(IgG, γ). Anti-CD 21 and anti-CD23 antibodies failed to stain the proliferative areas of the lymphoma cells. Somatic mutation and intraclonal microheterogeneity of the rearranged immunoglobulin heavy chain (IgH) gene variable region (VH gene) were examined. The VH gene exhibited 99% homology to the closest germline and no intraclonal microheterogeneity was found. These data revealed that the lymphoma cells possessed a class-switched IgH gene with little somatic mutation of the VH. This case is not a variant of follicular lymphoma derived from germinal center cells, but a variant of immunoblastic lymphoma derived from post germinal center cells.