The diagnostic value of silver nucleolar organizer region assessment in breast cytology.

Benign and malignant breast lesions in cytologic preparations can be difficult to distinguish. The authors applied the silver nucleolar organizer region (AgNOR) technique to cytologic preparations obtained from surgical specimens to evaluate its diagnostic usefulness in making this distinction. Sixty-two benign and 36 malignant lesions were examined. AgNORs were counted and evaluated using a subjective scoring technique to examine AgNOR size, shape, and clustering. The benign lesions had a mean count of 4.44 AgNORs/nucleus (95% CI, 2.4-6.5) and the malignant cases, 9.52 AgNORs/nucleus (95% confidence interval, 7.4-11.7; P < .0005). The median score for benign cases was 7 and for malignant cases, 13 (P < .0001). With a few exceptions, cases with high counts had high scores. The diagnostic accuracy of combined counting and pattern assessment was 90%. The likelihood ratio for correct diagnosis using AgNOR counting was 14:1 and for AgNOR scoring, 13:1.