THE ACCURACY OF INTRAOPERATIVE DIAGNOSES BASED ON EXAMINATION OF FROZEN-SECTIONS - A PROSPECTIVE COMPARISON WITH PARAFFIN-EMBEDDED SECTIONS

The accuracy of diagnoses based on examination of frozen sections was determined by comparing the results to those obtained by examination o f tissues prepared using conventional methods (formalin fixation, para ffin-embedded tissue). One hundred ninety-four specimens were examined using the frozen section technique; 37 were examined to confirm a ten tative diagnosis or to document lymph node metastasis and the remainde r were examined to diagnose an unknown pathologic process. Of the 194 specimens examined, an accurate, specific diagnosis was obtained in 16 1 (83%); in 19 (10%), the pathologic process was correctly identified, but a specific diagnosis was not obtained; and in 2 (1%) the diagnosi s was deferred. The remaining 12 (6%) were incorrectly diagnosed by th e frozen section technique. When the number of specimens in which a sp ecific diagnosis was obtained was combined with the number of specimen s in which the pathologic process was correctly identified, the overal l accuracy rate of the frozen section technique was 93%. There was no difference in the accuracy of the frozen section technique based on th e reason for submission of the sample, source of tissue submitted, or the type of pathologic process (i.e., inflammatory or neoplastic). Of the 12 incorrect diagnoses, 4 (33%) were because of sampling errors an d 8 (67%) were caused by interpretation errors. The proposed indicatio ns for the use of intraoperative frozen sections are: 1) to determine the nature of a pathologic process for which a preoperative diagnosis has not been established, 2) to determine the extent of spread of neop lastic tissue to lymph nodes and other organs, 3) to evaluate resectio n margins of a neoplastic process, and 4) to clarify situations where a discrepancy exists between the preoperative cytologic or histologic diagnosis and intraoperative gross pathology.