Value of cytology as an adjunctive intraoperative diagnostic method. An audit of 2,250 consecutive cases.

Abstract

To evaluate the role of intraoperative cytology (IC) in the improvement of diagnostic accuracy obtained by frozen section (FS) alone. Comparison of 2,250 intraoperative cytologies performed along with frozen sections, with the final diagnoses achieved on paraffin sections. In 18 cases the diagnoses were deferred until the paraffin sections at the time of intraoperative consultation. The diagnostic accuracy in distinguishing benign from malignant lesions by combined intraoperative cytology and frozen section was 99.2%. The accuracy rate is significantly higher than that reported in large series based on frozen section preparations alone. Sensitivity and specificity were, respectively, 98.2% and 100%. The diagnostic accuracy of each technique alone was 94.9% for FS (sensitivity 89.9%, specificity 97.9%) and 96% for IC (sensitivity 94.9%, and specificity 96.8%). Although specific diagnoses were more frequently formulated on the bases of frozen section examination, FSs were not diagnostic in 113 case in which cytology allowed a specific diagnosis. Our results emphasize the increasingly important diagnostic role of intraoperative cytology as an adjunct to frozen section. The approach does have limitations.