Characteristics and histology for the 2 patients who developed PTLD after rituximab. (A) Patient characteristics. (B) Histologic characteristics of case 1. (C) Histologic characteristics of case 2. DLBCL, diffuse large B-cell lymphoma; GCB, germinal center B cell; mPTLD, monomorphic PTLD; pPTLD, polymorphic PTLD.