PTLD Classification of 1988 (Nalesnik et al.)
Category	Lymphocyte Heterogeneity (Polymorphism)	Plasmacytic Cells	Necrosis	Underlying Architecture	Clonality#	Comments
Reactive Diffuse Plasma Cell Hyperplasia	Minimal	Marked	No	Intact	Not determined	Described, but relationship to PTLD undefined
Polymorphic PTLD	Prominent	Variable	Variable may be prominent	Disrupted*	17/31 (55%) with Monoclonal component	Includes Polymorphic Hyperplasia and Lymphoma of Frizzera et al.
Minimally Polymorphic PTLD	Minimal	Prominent	Variable	Disrupted	18/22 (82%) with Monoclonal component	Term not widely applied; synonymous with plasmacytoma
Monomorphic PTLD	None	Rare to None	Variable	Disrupted	5/5 (100%) Monoclonal	Synonymous with non-Hodgkin's lymphomas
Notes: *Early infiltrative lesions may not have recognizable architectural destruction; #Clonal composition was based on molecular or immunoperoxidase studies in individual cases.

Reference Nalesnik MA, Jaffe R, Starzl TE, Demetris AJ, Porter K, Burnham JA, Makowka L, Ho M, Locker J: The pathology of posttransplant lymphoproliferative disorders occurring in the setting of Cyclosporine A-Prednisone immunosuppression. Am J Pathol 133:173-192, 1988

University of Pittsburgh.