LAUSR

We identified six patients with Epstein‐Barr virus (EBV)‐negative extranodal diffuse large B‐cell lymphoma (DLBCL) and immunohistochemical expression of PD‐L1 on their tumor cells by examining 283 DLBCL cases with the PD‐L1 SP142 clone between 2015 and 2017. They consisted of two men and four women with a median age of 71 years, and were examined in an autopsy (n = 1) and biopsies from the adrenal gland (n = 2), skin (n = 1), pelvic cavity (n = 1), and kidney (n = 1). All showed a monomorphic population of large transformed B‐cells leading to diagnoses of DLBCL with two intravascular large B‐cell lymphoma (IVLBCL) and one de novo CD5+ type and were featured by an invariable immunephenotype: CD3‐, CD20+, BCL‐2+, and MUM1+. In addition, CD5 and CD10 were each detected in one case. All cases expressed PD‐L1 on >10% to >90% of tumor cells, which was confirmed with two other PD‐L1 antibodies (E1J2J and 28‐8). Three untreated patients had a rapid, lethal clinical course within 7 months after diagnosis; while, the remaining three achieved complete remission after treatment and were alive at the last follow‐up. We suggest immune evasion‐related extranodal large B‐cell lymphoma should be recognized beyond the currently identified entities of IVLBCL and de novo CD5+ DLBCL.