The reproducibility of the Lukes-Collins classification of non-Hodgkin's lymphomas in a retrospective reclassification.

In a retrospective reclassification of 148 non-Hodgkin's lymphomas the reproducibility of the Lukes-Collins classification used was tested by comparing a joint diagnosis with that of each author separately. Thirty-six percent of the lymphoma cases were follicular center cell lymphomas, the figure being clearly lower than that of materials published previously. The relatively high portions of small lymphocytic and mycosis fungoides lymphomas (20 and 10% respectively) were also deviant findings in comparison to formerly published retrospective materials. In this reproducibility study the cases of disagreement were usually proved to have happened within lymphoma groups with an equivalent prognosis. An exception was the relatively high disagreement rate between the subclasses of small lymphocytic and small non-cleaved lymphomas, and this represents the most important finding clinicopathologically. The results of the study indicate that the Lukes-Collins classification as such does not cover the whole spectrum of non-Hodgkin's lymphomas. The studies published already give some clues as to the fact that distribution and cell types of non-Hodgkin's lymphomas vary in different areas of the world.