[Pathohistology of non-Hodgkin's lymphomas: recent progress].

After the recognition of the various phase of the physiologic differentiation and transformation of lymphocytes (from the stem cells over T-prolymphoblasts and lymphoblasts to the effector-T-cells and over the B-lymphoblasts, B1-lymphocytes to the lymphatic plasma cells and, respectively, over centroblasts, centrocytes, B2-lymphocytes to the Marschalko plasma cells) it became clear that the non-Hodgkin-lymphomas correspond to the individual, apparently blocked phases of the differentiation and transformation. The classification after Kiel distinguishes non-Hodgkin-lymphomas of a malignity of low degree (CLL, centrocytoma, centroblastic-centrocytic lymphoma, immunocytomas) and of high degree (T-lymphoblastoma, centroblastoma, immunoblastoma). An essential part of these tumours may be diagnosed with the help of the usual light-microscopic methods. When several supplementing cytochemical and immunocytological methods are used, nearly all non-Hodgkin-lymphomas are to be characterized, though border-line cases and non-classifiable non-Hodgkin-lymphomas rarely appear, but they appear.