A Rare Case of Signet Ring Cell Lymphoma and Review of the Literature

Signet ring cell lymphoma (SRCL) is a non-Hodgkin's lymphoma with a very rare variant. Although this morphology is frequently seen in follicular lymphoma, it can also be observed in the group of diffuse large B-cell lymphomas. A seventy-six year old woman with known diagnosis of gastric adenocarcinoma, tubular type, moderately differentiate presented with a mesenteric lymphadenopathy with high FDG uptake (SUVmax: 21.3) in PET/CT during follow-up. A tru-cut biopsy was performed for histopathological diagnosis. Diffuse infiltrative singet ring neoplastic cells showed negativity for PanCK, CK7, CK20, S100, SMA, calretinin and vimentin. The panel was then expanded to include SRCL, a rare variant of lymphoma. Additional immunohistochemical evaluation revealed positivity for CD20, CD19, PAX-5 and Bcl-2. Ki-67 proliferation index was about 80%. CD3, CD30, Myc, Bcl-6, ALK, Cyclin-D1, CD23, CD10, CD21, and MUM-1 were negative. EBER was also negative by chromogen in situ hybridization (CISH). Based on these data, diffuse large B-cell lymphoma (DLBCL) was considered. We herein reported a case of signet ring cell lymphoma discussed its clinical and morphological features with regard to the literature.