[1054] Factors Influencing Accuracy of Frozen Section Diagnosis of Ovarian Mucinous Tumors; a Review of 100 Cases.

Brian Harmon, Sonya Hwang, Travis Parker, Michael Pearl, Carmen Tornos. Stony Brook University Medical Center, NY

Background: Ovarian mucinous tumors tend to be large and histologically heterogenous. Many studies point to them as the major source of diagnostic discrepancies between intraoperative and final diagnosis of ovarian masses. The aim of this study was to assess the accuracy of frozen section (FS) diagnosis of ovarian mucinous tumors and to identify possible factors affecting the accuracy rate.
Design: We identified 100 consecutive ovarian mucinous tumors that underwent FS evaluation at the request of our Gynecological oncologists from January 2000 to August 2010. All H&E slides from the FS's and permanent sections were reviewed. Parameters evaluated included: tumor size and gross appearance, bilaterality, previous history of malignancy, number of FS blocks submitted, and pathologist experience in gynecological pathology.
Results: The final diagnosis included 28 mucinous cystadenomas, 27 metastatic mucinous carcinomas, 24 borderline tumors intestinal type, 16 primary ovarian carcinomas, and 5 borderline tumors endocervical type. All benign tumors were classified correctly at the time of frozen section, as were 25 of the 27 metastases, and the other 2 cases were deferred. The table shows results of FS and final diagnosis of all primary ovarian tumors.

Results of FS and final disgnosis of all primary ovarian tumors

Frozen diagnosis	Final Diagnosis
	Benign	Borderline	Malignant
Benign	28	7	1
borderline	0	13	6
Malignant	0	0	6
Deferred	0	9	3

There were no false positive cases that underwent unnecessary staging. Underdiagnosis occurred in 14/100 (14%). Agreement between frozen section diagnosis and final diagnosis was observed in 72/100 cases (72%). Agreement in non-benign tumors was seen in 44/ 72 cases (61%). The sensitivity was 100%, 44.9%, and 37.5% for benign, borderline, and primary malignant tumors. The corresponding positive predictive value was 77.8%, 68.4%, and 100%. In univariate and multivariate analysis tumor diameter was the only predictor of underdiagnosis.
Conclusions: Intraoperative frozen section diagnosis of mucinous tumors is reliable for benign tumors and metastases, but it has a low sensitivity for borderline tumors and ovarian carcinomas. Surgical management based on intraoperative frozen section diagnosis should be used with caution.
Category: Gynecologic & Obstetrics

Monday, February 28, 2011 11:45 AM

Platform Session: Section D, Monday Morning