[Quality control of intraoperative diagnosis. Annual review of 1490 frozen sections].

A retrospective evaluation of the accuracy of frozen section diagnoses over 1-year period has been carried out. Of 20998 surgical pathology specimens accessioned during 1991, 1265 (6.0%) had intraoperative pathologic consultation; 1490 were the frozen section examinations effectively carried out, with an average of 1.2 frozen section diagnoses per case. Of all frozen sections performed, 4.6% were deferred; in the remaining cases, the concordance between frozen sections and the final histologic diagnoses was 97%. The reasons for diagnostic discordances were gross sampling error (51.2%), misinterpretation (44.2%), microscopic sampling (9.3%), technical problems in sectioning (2.3%). We believe that a similar continuous monitoring should be performed in every pathology department, to recognize the reasons of errors and, if possible, to reduce them.