6th ESACP Congress, Heidelberg, April 7-11, 1999

A037
AGNOR-QUANTIFICATION FOR IDENTIFICATION OF TUMOR CELLS IN EFFUSIONS OF THE SEROUS MEMBRANES
Böcking A, Buckstegge B, Murach BL, Motherby H, Pomjanski N

Inst.Cytopathology, Heinrich-Heine-Uiversity, Düsseldorf, Germany

Aims: To find out sensitivity and specificity of AgNOR-staining and of different modes of dot-counting in mesothelial and/or abnormal cells in effusions of the serous membranes for identification of tumor cells. Material and Methods: 20 effusions with carcinoses, 20 with malignant mesotheliomas, and 20 without tumor cells in the clinical follow-up were investigated. 20 effusions had tumor cell negative, 30 positive, and 10 equivocal cytological diagnoses. AgNOR-dots were counted subjectively in 100 mesothelial or abnormal cells per case, 1. all but those in clusters as one dot, 2. as satellites, 3. number of clusters. Results: AgNOR-counts as satellites ranged from 1.17-2.33 in reactive mesothelial cells, from 2.73-10.08 in mesotheliomas and 4.79-11.23 in carcinoses. Counts of all AgNOR-dots, those in clusters counted as one ranged from 2.50-4.37 in reactive cells, from 4.68-11.18 in mesotheliomas and 5.90-12.12 in carcinoses. Mean numbers of clusters per nucleus ranged from 1.0-2.15 in reactive cells, from 0.44-1.50 in mesotheliomas and from 0.80-1.59 in carcinoses. Using a threshold of 2.5 AgNOR-dots as satellites 100 % sensitivity and specificity was achieved for the differentiation of reactive mesothelial and mesothelioma cells as well as of carcinoma cells in effusions. In all (n=10) cytologically doubtful cases (all mesotheliomas) diagnoses could be decided correctly as to the occurrence of tumor cells in the clinical follow-up. Discussion: Counting the number of AgNOR-dots occurring as satellites in nuclei of mesothelial or diagnostically doubtful atypical cells seems to be superior to counting all AgNORs per nucleus or per cluster. Applying the experimentally found threshold of 2.50 AgNORs as satellites in 100 nuclei results in a 100 % correct rate of tumor cell identification including malignant mesothelioma cells without false positive diagnoses so far. These results are especially encouraging concerning a sensitive early cytological diagnosis of malignant mesothelioma in effusions.