Cell volumes and dna distributions of normal and neoplastic human lymphoid cells

This study was designed to test the value of flow quantitative cytology in the diagnosis and classification of lymphoid neoplasias. Cells obtained from a variety of lymphoreticular malignancies as well as from non‐heoplastic lymphoid tissues and peripheral blood were assessed for their size distributions and their DNA contents using flow microfluorometry. The electronic modal volume (MV), the coefficient of variation of cell size (CV) and the percentage of cells containing DNA quantities between diploid and tetraploid values (S) were compared with the diagnoses determined by conventional morphological criteria. There was a general correlation between the size distribution of the cell populations as observed by optical methods and that measured electronically. Malignant populations obtained from peripheral blood could be differentiated from normal blood mononuclear cells. Normal thymic populations were distinctly different from all other populations due to their low MV. All „histiocytic”︁ (large cell) lymphomas showed either high MV or high CV. Most tumors composed morphologically of small cells displayed low MV. The cells of Burkitt's tumor also showed relatively high MV and/or CV but to a lesser extent than the „histiocytic”︁ lymphomas. All hairy cell populations showed bimodal distributions and high MV. As expected, most mixed cell lymphomas showed high CV values. Marked variability of MV and/or CV were observed among lymphocytic lymphomas of intermediate differentiation and lymphoblastic lymphomas. A general correlation was also found between the percentage of cells in S in individual malignancies and their expected clinical behavior. Neoplasms known to be of low grade aggressiveness displayed low S values. Burkitt's lymphomas showed in all cases the highest percentage of S and lymphoblastic and „histiocytic”︁ lymphomas displayed a wide range of S values. Cases of diffuse „histiocytic”︁ lymphoma with a previous history of nodular lymphoma showed lower S percentages than those appearing de novo. These observations suggest that the rapid, reproducible results provided by flow cytologic analysis may both aid in the diagnosis and classification of lymphoid tumors and also eventually contribute to predicting and monitoring therapeutic responses.