Cytologic evaluation of body cavityfluids is useful to detect malignancy within the pleural and peritoneal spaces. A definitive diagnosiv cannot always be made on cytologic evaluation alone. As malignant processes may show abnormal DNA content, DNA analysis of effusions may be useful. Therefore, we determined the DNA content of 37 effusions by flow cytometry (FC) and image analysis (IA) using the CAS 200. Of the 37fluid.v evaluated, 18 were cytologically malignant, 15 benign, and four atypical. Overall, 22 fluids (60%) showed concordance between I.% and IA.
None of the benign jluids were aneupbid. AN showed diploid histograms or diploidy with increased prol$eruting cells. Three of four atypical fluids had increased proliferating cells by either FC or IA, whereas one was diploid by both methods. Aneuploidy was detected in J3 ma1ignantjuids:five were aneupioid by both methods and eight by only one method. I A identixed aneuploidy i n j v e of those eight cases, while three were identifed by FC Three of the cytological& malignant fluids were diploid by both methods, and two showed increased proli$rating cells by IA and dipioidy by PC. The specijkity of both methods was 100%. However. the sensitivity of identifying a malignant fluid by aneuploidy is low, 44% for FC and 55% for IA. I A appears to identijysmall aneuplaid populations more frequently than FC. The detcction of aneuploidy in effusions is highly suggestive of malignancy, and the Combination of both techniques gives the highest detection rate (71? %). However. neither are as sensitive as traditional cytologic evaluation with the occasional use of additional histochemical stains.