Morphological classification of non-Hodgkin malignant lymphoma. II. Comparison between Rappaport's classification and the Kiel classification.

In a retrospective survey of 334 cases of non-Hodgkin lymphoma (NHL), 250 cases could be classified according to both Rappaport's classification and the Kiel classification. All patients initially in stage I had an excellent prognosis irrespective of histology, whereas patients in stages II, III and IV had a worse prognosis that did not significantly differ between stages. Rappaport's classification could separate stages II-IV into 2 different prognostic groups, one favourable and one unfavourable group. According to the Kiel classification, 3 prognostic groups - favourable, intermediate and unfavourable - were found. The survival rate for favourable Rappaport fell in between favourable-Kiel and intermediate-Kiel. Both subgroups within favourable-Rappaport (nodular lymphomas and diffuse well differentiated lymphomas) could actually be subdivided by the Kiel classification into one group with a more truly favourable behaviour and one with an intermediate behaviour. The extent of follicularity among nodular lymphomas and the presence of plasmacytoid differentiation among the small lymphocytic lymphomas were found to be of prognostic importance. In conclusion, we found that the Kiel classification separated the more indolent lymphomas better than Rappaport's classification. No preference was found concerning the high grade lymphomas.