Objective: Malignant cells are known to display greater argyrophil staining for nucleolar organizer regions (AgNORs) than for benign cells due to their active proliferation. In this study we assessed the diagnostic value of AgNOR staining on 47 fine needle aspiration cytologic specimens of lung previously stained with the May-Grünwald-Giemsa (MGG) method.
Methods: Cytologic specimens obtained from fine needle aspiration of the lung in 47 proven cases prestained with the MGG technique were destained and restained with the AgNOR method. Seventeen of them were benign and 30 malignant. To differentiate malignant from benign entities, the highest median value for AgNOR number (AgNOR score) obtained from the benign cases was chosen as a cutoff point (test specificity, 100%).
Results: AgNOR scores of malignant cases were significantly higher than those of benign cases (P < .001). There was no significant difference between two subgroups of benign diseases or among four subgroups of malignant diseases. The sensitivity of the AgNOR score was 93% (28/30) in providing a diagnosis of malignancy when the cutoff value was set at 6.
Conclusion: The AgNOR technique may be of considerable value in aiding a diagnosis of malignancy, especially when the score is > 6.