Ann Arbor Stage Classification of Hodgkin's Disease

I = Infestation of only one lymph node region

II1 = Infestation of two adjacent lymph node regions on only one side of the diaphragm, i.e. either above or below the diaphragm

II2 = Infestation of two non-adjacent or more than two adjacent lymph node regions above or below the diaphragm

III = Infestation of lymph node regions above and below the diaphragm

IV = diffuse or disseminated infestation of lymph nodes and extralymphatic tissues