Primary Gastric EBV-positive Diffuse Large B Cell Lymphoma (DLBCL) of the Elderly with Plasmablastic Differentiation.

Epstein-Barr virus (EBV)-positive diffuse large B cell lymphoma (DLBCL) of the elderly is a rare subtype of B-cell neoplasms. Primary gastric EBV-positive DLBCL of the elderly with partial plasmablastic phenotype is extremely rare. Differentiation of EBV-positive DLBCL of the elderly with partial plasmablastic phenotype from true plasmablastic lymphoma (PBL) is difficult and very important from the therapeutic and prognostic point of view. Here we report a case of a 59-year-old man with upper gastrointestinal bleeding. The esophagogastroduodenoscopy revealed a 2-cm malignant-appearing non-bleeding gastric ulcer in the gastric cardia. Biopsy showed ulcerated tissue with atypical lymphoid cell infiltrate, morphologically consistent with immunoblasts. The atypical large cells were positive for CD20, PAX5, MUM-1, and a subset of large cells was positive for CD30, BCL6 and CD138. Ki-67 proliferation index exceeded 90% of the tumor cells. In situ hybridization (ISH) for EBV-encoded RNAs (EBERs) was extensively positive. Kappa/Lambda ISH showed lambda restriction. The final diagnosis was primary gastric EBV-positive DLBCL of the elderly with plasmablastic phenotype. The patient finished 5 cycles of R-DA-EPOCH with significant clinical improvement. To the best of our knowledge, this is an extremely rare case of primary gastric EBV-positive DLBCL of the elderly with plasmablastic phenotype.