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

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).