Early diagnosis of mesothelioma in serous effusions using AgNOR analysis

OBJECTIVE: To compare tile results of conventional cytology, DNA image cyto metry, immunocytochemistry and argyrophilic nucleolar organizer region (AgN OR) analysis for the diagnosis of malignant cells in serous effusions. STUDY DESIGN: One hundred twenty effusions, 40 with carcinoses, 40 with mal ignant mesotheliomas and 40 without tumor cells on follow-up were studied b y conventional cytology and three adjunctive methods. RESULTS. Unequivocal tumor cells were detected in 92.5% of effusions due to carcinoses and in 45% due to mesotheliomas, Applying immunocytochemistry w ith BerEP-4 positivity and DNA image cytometry with aneuploidy as a marker revealed 100% of carcinoses and 71.7% of mesotheliomas. Applying the experi mentally found thresholds of 2.5 AgNORs as "satellites" and 4.5 AgNORs as " satellites and clusters" together as mean values per nucleus resulted in a 95% correct rate of mesothelioma and 100% rate of carcinoma cell identifica tion without false positive diagnoses. CONCLUSION: AgNOR analysis may be a useful adjunct to other methods in the routine diagnosis of malignant serous effusions. It seems to be the most se nsitive method in early cytologic diagnosis of mesotheliomas in effusions. Seventy-three percent of malignant mesotheliomas were diagnosed cytological ly at first on effusions. Forty-seven percent of patients with malignant me sotheliomas were identified at the early tumor stage T1 N0 M0.