The aim of these last two sessions is to assess to what extent recent pathologic and biologic considerations can be used for diagnosis and treatment. This morning’s session is devoted to staging. Staging constitutes one of the major advances of the last decade for malignant lymphoma. As a result of speculations about the propagation of this disease, laparotomy was introduced by the Stanford group. In turn, laparotomy and modern staging have provided important information on the natural history of malignant lymphoma. In particular, the incidence of occult involvement of spleen in Hodgkin’s disease or of bone marrow in non-Hodgkin’s lymphoma is much higher than previously suspected.