Significance of AgNOR count in differentiating malignant cells from reactive mesothelial cells in serous effusions.
OBJECTIVE
To distinguish reactive mesothelial cells from malignant cells in serous effusions using silver staining of nucleolar organizer regions (AgNOR) applied to ethanol-fixed cytologic preparations.


METHODS
One hundred aspirated samples of benign and malignant effusions were studied using the one-step silver staining method. Eight cytologically atypical samples were also included in the study.


RESULTS
In malignant cells the mean AgNOR count was 4.72 +/- 0.76 (+/- SD), and the AgNORs were irregular in shape, while in benign mesothelial cells AgNORs were comparatively larger, single dots with a mean count of 1.92 +/- 0.23. Of the cytologically atypical samples, five were in the malignant range. The others were within benign limits. Repeat cytology of the second aspirate confirmed that finding.


CONCLUSIONS
AgNOR study appears to be clinically useful as an additional diagnostic tool for use in ascitic and pleural fluid samples when the cytologic diagnosis is difficult.
Sujathan
K
K
Division of Cytopathology, Regional Cancer Centre, Thiruvananthapuram, Kerala, India.
Kannan
S
S
Pillai
K R
KR
Chandralekha
B
B
Amma
N S
NS
Nair
M K
MK
D000230:Adenocarcinoma / Q000473:pathology; D001201:Ascites / Q000473:pathology; D001707:Biopsy, Needle / Q000379:methods; D002277:Carcinoma / Q000473:pathology; D003581:Cytodiagnosis / Q000379:methods; D003937:Diagnosis, Differential; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000473:pathology; D008545:Melanoma / Q000473:pathology; D009369:Neoplasms / Q000145:classification / Q000473:pathology*; D009697:Nucleolus Organizer Region / Q000473:pathology*; D010996:Pleural Effusion / Q000473:pathology*; D013194:Staining and Labeling / Q000379:methods