Intraoperative imprint cytology: its significance as a diagnostic adjunct.

We retrospectively evaluated 664 specimens submitted for intraoperative frozen-section analysis for which cytologic imprints or smears were also prepared; 238 (36%) were malignant neoplasms. These preparations were retrospectively evaluated independently by three reviewers of varied experience in the detection of malignancy. The number of false-positive and false-negative results were recorded, and various assessment parameters (sensitivity, specificity, efficiency, and predictive value) were calculated. The imprint was of chief value as an adjunct to the frozen section, particularly in avoiding false-positive and, to a lesser extent, false-negative interpretations. Experience with the use of intraoperative cytology demonstrated the technique to be of value in providing abbreviated preparation time (3-5 min); supportive diagnostic information when frozen section was equivocal; diagnostic information when frozen-section evaluation could not be done (e.g., excessively small sample); contributory information for final diagnosis on difficult cases; and excellent teaching material for cytopathology.