The value of imprint cytology in tumor diagnosis: a retrospective study of 522 cases in northern China.

The diagnostic value of imprint cytology in a retrospective study of 522 histologically proven tumors from various sites is reported. The total diagnostic accuracy was 92.9% (485/522); for benign tumors, the accuracy was 97.2% (208/214); for malignant tumors, the accuracy was 89.9% (277/308). Overall, the false-positive and false-negative rates were 0.8% (4/522) and 4.8% (25/522), respectively. The rate of "malignancy suspected" diagnosis, i.e., diagnosis undetermined, was 1.5% (8/522). Imprint cytology can sometimes provide information on the histogenesis and histologic patterns of the tumor, but it cannot provide information on the depth of infiltration. Despite that limitation and the percentage of false-negative results that it yields (8.1% of malignancies in this study), imprint cytology has wide applicability in the diagnosis of both benign and malignant tumors.