They had a PMBCL-like GEP signature, and carried somatic mutations that were seen frequently in PMBCL (TNFAIP3 and CD58) instead of those often seen in ABC or GCB DLBCL (TP53, CD79B, MYD88, CREBBP, and EZH2). This evidence concerns the gene CREBBP and aneurysmal bone cyst.