[1227] The Value of Frozen Section Diagnosis in Thyroid Pathology

NC Fernandez, F Lucas, Q Zhai. University of Cincinnati, Cincinnati, OH; Greater Cincinnati Pathologists, Inc, Cincinnati, OH

Background: Intraoperative frozen section (FS) for thyroid specimens is a useful tool to the surgeon, although its reliability to detect malignant lesions is highly variable. To compare the sensitivity of frozen section for diagnosis of thyroid pathology we studied our experience in a teaching hospital.
Design: The consecutive records of 369 patients who underwent thyroid surgery during a five year period (2004 to 2009) were analyzed, and those cases with FS diagnosis were selected. The final diagnoses based on subsequent permanent paraffin block fixation were grouped as papillary carcinoma, follicular adenoma, multinodular goiter/hyperplasia, Hashimoto's thyroiditis, anaplastic carcinoma, and lymphoproliferative disorders. These were compared with the correspondent FS diagnosis and classified as concordant, concordant but deferred for permanent, or discordant. The sensitivity was calculated, and the causes for discordance were tabulated.
Results: A total of 179 consecutive cases of thyroid surgery with FS diagnosis were identified and analyzed. The distribution of final diagnoses was: papillary carcinoma, (n=36); follicular adenoma, (n= 19); multinodular goiter, (n=64); Hashimoto's thyroiditis, (n=19); Hurthle cell adenoma, (n=6); lymphoproliferative diseases, (n=5); anaplastic carcinoma,(n= 4). Overall, the sensitivity of frozen section diagnosis for thyroid pathology in our institution was 75%. The sensitivity of frozen section for papillary carcinoma was 50%. Papillary carcinoma was an incidental finding in 8 cases (24.2%), found after additional sampling for permanent sections. The sensitivity for the diagnosis of follicular adenoma was 89%, for multinodular goiter 95%, for Hurthle cell adenoma and anaplastic carcinoma 100%, and for lymphoproliferative disorders was 80%. For Hashimoto's thyroiditis the sensitivity was 26%. Six of these discordant Hashimoto cases had diagnosis of papillary carcinoma, whereas three were diagnosed as follicular adenoma.
Conclusions: The sensitivity of frozen section in our institution is comparable with that of others reported in the literature, and it remains a useful resource for decisions regarding the extent of the surgical procedure. Factors such as suboptimal sampling, freezing artifact, and the experience of the pathologist interpreting the slides play a role in the concordance with the permanent H&E sections. Awareness of these factors and a methodical approach to handling and sampling the specimen is recommended to limit potential pitfalls.
Category: Head & Neck

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 171, Wednesday Morning

 

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