Studies on morphological typing of argyrophilic nucleolar organizer regions

Morphological typing of argyrophilic nucleolar organizer regions (AgNOR) in 300 cases of malignant tumors and 140 cases of benign lesions was analyzed and five morphological types of AgNOR were described in detail. In malignant tumors, the diffuse type (78%) was the most frequently seen, and in benign lesions, the nucleolar type (92.85%); the difference was thus highly significant (P < 0.001). The intranucleolar and aggregate types were not observed in benign lesions. There was no obvious difference in the proportion of the mixed type in benign and malignant lesions (P > 0.05). The relationship between grade of malignancy and morphological typing of AgNOR and its clinical significance are discussed.