Morphometric analysis of chronic B-cell leukemias--an aid to the classification of lymphoid cell types.

In order to evaluate the ultrastructural features which may be of relevance in distinguishing cells from the various chronic B-cell leukemias, a morphometric analysis was performed on a large number of cells from each disease group. The parameters selected were: cell size, nucleo: cytoplasmic ratio, chromatin condensation, size of the nucleolus and degree of irregularity of both the nucleus and the cytoplasmic outlines. The mean values obtained for each parameter for each disease group were compared statistically. In disorders in which the cells have villous cytoplasmic projections, the quantitative analysis of the cellular features was helpful to characterise the different types of B cells involved. Thus, cells from cases of splenic lymphoma were found to be different from those of hairy cell leukemia, and a variant form of HCL was also identified by its distinct ultrastructural features. Similarly cells from chronic lymphocytic, prolymphocytic leukemia and an intermediate group CLL/PL were identified by the size of the nucleolus and the degree of chromatin condensation. The morphometric findings provided an objective morphological basis for the differential diagnosis between these closely related B-cell leukemias which was further supported by differences in the cells immunophenotype.