Comparative morphometric analysis of nuclear area and shape in peripheral T-zone lymphomas and in paracortical areas of normal and reactive lymph nodes

The areas and shapes of cell nuclei were morphometrically analyzed in peripheral T-zone lymphomas, which have a characteristic nuclear pleomorphism, as well as in paracortical areas of normal and reactive lymph nodes; the aim of the study was to compare the neoplastic and nonneoplastic lymphoid cell populations. Although the means and standard deviations (SDs) of nuclear area and shape features differed significantly between the T-zone lymphomas, reactive nodes and normal nodes, there was considerable overlap between the lymphomas and the reactive lymph nodes in all of the features investigated. Therefore, the composition of populations of nuclei was studied. In lymphomas, the frequencies of regular and irregular nuclei were about the same in all nuclear area classes, whereas increasingly larger nuclei had an increasingly regular shape in reactive lymph nodes. An attempt to classify the cells, divided into those with small nuclei (<25 sq μm) and those with large nuclei (>25 sq μm), on the basis of their morphometric shape features showed the usefulness of form factors in the class of nuclei with a large area. The results show that, while means and SDs of nuclear area and shape are not very accurate descriptors of the differences between the T-zone lymphomas and nonneoplastic lymph nodes, analysis of the percentage of regularly shaped nuclei in a certain nuclear area class can describe the differences much more accurately. The compositional differences in nuclear shape are in agreement with subjective impressions and can objectively support the pathologist's qualitative impression of pleomorphism in malignant T-zone lymphomas.