Intraoperative Frozen Section Examination of Endometrial Carcinoma: Do Diagnostic Discordances with Final Pathologic Diagnosis Impact the Operative Treatment Algorithm?
F Medeiros, A Mariani, KC Podratz, GL Keeney. Mayo Clinic, Rochester, MN
Background: Intraoperative frozen section examination of hysterectomy specimens is routinely used to guide the decision of surgical staging in patients with endometrial carcinoma. The aim of this study is to assess the accuracy of frozen section diagnosis of endometrial carcinoma when compared with permanent sections and how discordances can affect the operative treatment algorithm.
Design: The study comprised 422 consecutive patients undergoing hysterectomy for endometrial cancer at the Mayo Clinic between January of 2004 and December of 2006. The intraoperative frozen section report was compared with the final pathology report to access for discordances, including tumor type, size and grade, myometrial invasion and lymph node status.
Results: There were 340 endometrioid adenocarcinomas, 61 serous carcinomas, 12 clear cell carcinomas, 5 mixed carcinomas and 4 undifferentiated carcinomas. A median of 4 endomyometrial sections (range 2-15) were evaluated per case at the time of frozen section. In 14 (of 422) cases, the diagnosis was deferred to permanent sections to further characterize a poorly differentiated carcinoma or hyperplasia from adenocarcinoma. In 50 cases (11.8%) the pathology report was addended or amended. The most frequent reason for amendment (N = 19, 37%) were microscopic foci of metastatic carcinoma to lymph nodes that were not detected at frozen section. In 5 instances (10%) there was a change in tumor type. In 3 cases the frozen section diagnosis was serous carcinoma and permanent sections showed mixed serous and clear cell carcinoma. In 2 cases the tumor was initially classified as endometrioid FIGO grade 2 and 3, respectively and on permanent sections a serous component was identified. In 4 cases (8%) the process was initially categorized as endometrial hyperplasia and on the following day FIGO grade 1 endometrioid adenocarcinoma was recognized. In only one occasion the reason for amendment was the presence of superficial myometrial invasion. There was no change in depth of myometrial invasion or tumor dimension in any of the cases.
Conclusions: Despite the occurrence of minor discordances between the frozen section and final diagnoses, these changes did not usually affect the factors used in intraoperative decision-making. In only one case the change in tumor type and grade could have potentially affected the operative treatment algorithm.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 156, Wednesday Afternoon