Reconceptualizing the framework for categorizing the heterogeneous spectrum of lymphoproliferation in pediatric PTLD. Traditional PTLD classification is based on morphological features stratified as nondestructive, polymorphic, monomorphic, and classical Hodgkin lymphoma (CHL) PTLD. This revised stratification highlights the heterogeneity of monomorphic PTLD and demarcates a threshold beyond which quintessential EBV-driven lymphoid hyperplasia or neoplasia transforms into malignant lymphoma. EBV⁺ DLBCL in particular straddles the threshold between quintessential PTLD and posttransplant lymphoma. Ovals with purple borders indicate entities that are typically EBV⁺, and ovals with blue borders indicate entities that are often EBV⁻. HGBL NOS, high-grade B-cell lymphoma, not otherwise specified and other gray-zone, Burkitt-like mature B-cell lymphomas; PLASMA CELL, plasma cell neoplasm; T/NK CELL, T/NK-cell lymphoma; TX, transplant.