Posttransplant lymphoproliferative disorders following liver transplantation: Where are we now?

Table 1 World Health Organization classification posttransplant lymphoproliferative disorder

	Early lesions	Polymorphic PTLD	Monomorphic PTLD
Underlying architecture	(Partially) preserved	Destructed	Destructed
Cells	Plasma cells, small lymphocytes and immunoblasts	Complete spectrum of B cell maturation	Fulfill criteria for lymphoma
Immunohistochemistry	No diagnostic value	Mixture of B and T cells	Most cases CD20 positive
EBV	100%	> 90%	+/- 70%
Clonality	In most cases polyclonal	Variable	Monoclonal
Oncogenic mutations	No	Variable (BCL6)	Oncogenes (N-Ras, c-MYC,…) and tumor suppressor genes (p53,…)

PTLD: Posttransplant lymphoproliferative disorder; EBV: Epstein Barr virus.

Table 2 Ann Arbor staging system for lymphoproliferative disorders

Stage I	Involvement of a single lymph node region (I) or one extralymphatic site (IE)
Stage II	Involvement of two or more lymph node regions, at the same side of the diaphragm (II) or local extralymphatic extension plus one or more lymph node regions at the same side of the diaphragm (IIE)
Stage III	Involvement of lymph node regions on both sides of diaphragm (III) which may include the spleen (IIIS) or accompanied by local extralymphatic extension (IIIE) or both (IIIES)
Stage IV	Diffuse or disseminated involvement of one or more extralymphatic organs or sites, with or without associated lymphatic involvement

Each stage number is followed by either A (absence of B-symptoms) or B (presence of B-symptoms: unexplained weight loss > 10% baseline during 6 mo before, unexplained fever > 38 °C, night sweats).