Image cytometry analysis of Feulgen-stained nuclei in 72 lipomatous lesions including atypical lipomas and well-differentiated liposarcomas.

Well-differentiated lipomatous tumors constitute a histopathologic category whose nomenclature has been controversial, particularly with respect to the distinction between atypical lipomas of the extremities and well-differentiated liposarcomas of the retroperitoneum. To determine whether there were differences in image analytic parameters between these neoplasms, 72 lesions including 21 typical lipomas, 7 atypical lipomas, 16 retroperitoneal and 5 nonretroperitoneal well-differentiated, 9 dedifferentiated, and 14 pleomorphic liposarcomas were submitted to the computer-assisted microscopic analysis of Feulgen-stained nuclei. This methodology enabled four groups of variables to be calculated. These included: (1) quantitative chromatin pattern description (14 variables); (2) the measurement of proliferative activity (1 variable); (3) nuclear DNA content (DNA ploidy level, 5 variables); and (4) the measurement of cell density and topographical cell nuclei organization (2 variables). The results strongly suggest that atypical lipomas, whether superficial or deep, and well-differentiated liposarcomas, whether retroperitoneal or not, belong to the same category in terms of the variables analyzed.