Lymphocyte nuclear morphology in diffuse well-differentiated lymphocytic lymphoma. Comparative morphometry of normal lymphoid tissues, non-Hodgkin's lymphoma, and Hodgkin's disease.

Precise morphologic data on the relationship of diffuse well-differentiated lymphocytic lymphoma (DWDLL) to other non-Hodgkin's lymphomas (NHLs) are lacking in current classifications of lymphomas. Morphometry of plastic-embedded tissues describes details of the mean nuclear parameters and distribution of lymphocyte-types in 14 cases of DWDLL in nodal and extranodal sites. The results indicate that the proportion of small (unstimulated or nontransformed) lymphocytes in DWDLL varies from 50% to 86%. The mean nuclear area of small lymphocytes in DWDLL is either within the size range or somewhat smaller, and many examples are more irregular in shape, than the small lymphocytes in germinal centers that are morphologically comparable with the majority of lymphocytes in DWDLL and mantle zones. The morphologic relationship of DWDLL to other NHLs, Hodgkin's disease, and paracortical, mantle, and germinal center lymphocytes in lymphoid-reactive hyperplasia was established by morphometric analysis of the nuclear profiles of small lymphocytes. The small (nontransformed) lymphocytes in those subtypes of NHL other than DWDLL have abnormally small and more irregular nuclear profiles than those in normal small lymphocytes, or the small-lymphocyte population of Hodgkin's disease. Such findings may be of diagnostic significance to pathologists.