A histologic and flow cytometric study of Kaposi's sarcoma.
One hundred forty-three biopsies of Kaposi's sarcoma (KS) from 96 patients were assessed histopathologically, and mitoses were counted. Ninety-seven samples from 66 patients were analyzed by flow cytometry. Six of 97 (5.8%) KS lesions were DNA aneuploid with a clustering around a DNA index of 1.5 (range, 1.4 to 1.6). The median percentage of S-phase plus G2-phase cells (%S + G2) was 16.7%. Increasing mitotic counts and %S + G2 were seen with progression of the phase and pattern of disease. Nodular KS and spindle cell predominant KS had the highest mitotic counts and %S + G2, with nodular KS larger than 4 mm having a higher mitotic count than those smaller than 4 mm. These findings suggest a low level of DNA aneuploidy in KS and important changes in the level of cell proliferation with the phase and pattern of the disease. However, flow cytometry does not solve the dilemma of whether KS is a hyperplastic or neoplastic process.