Utilization and Value of Frozen Section in the Diagnosis of Thyroid Cancer
A Acurio, JB Taxy. University of Chicago, Chicago, IL
Background: In the era of FNA evaluation of thyroid nodules, the use of frozen section (FS) in the management of patients who require surgery is controversial. FS, including its complementary use of imprints, may be unnecessarily redundant. Since treatment for thyroid cancer is a total or near total thyroidectomy an intraoperative diagnosis of cancer will avoid a second procedure. FNA has been a valuable form of preoperative evaluation primarily because the diagnosis of papillary carcinoma relies on features of nuclear morphology. FNA is less valuable in separating true follicular neoplasms from colloid nodules and of no use in the diagnosis of follicular carcinoma. The value of FS in this context is debatable since the diagnosis of follicular carcinoma requires clear-cut vascular invasion, a rare event which is sampling dependent. This study examines the utilization and value of FS in establishing an intraoperative diagnosis of thyroid cancer.
Design: We reviewed 271 thyroid FNA reports and subsequent thyroidectomies from December, 2004 to July, 2007 comparing preoperative FNA, intraoperative FS and final pathologic diagnosis. Only patients with lobectomies were included.
Results: Of the total, 97 patients underwent surgery with FNA diagnoses suggestive of follicular neoplasm or positive of papillary carcinoma. Of these, 76 also had FS examinations with the following results: papillary carcinoma (14), follicular tumor (38), and colloid nodules (12). There were no FS diagnoses of follicular carcinoma. On permanent examination, there was a total of 24 confirmed cases of papillary carcinoma: 4 with an indeterminate FNA diagnosis but confirmed as papillary carcinoma by FS; 2 deferred FS, 6 not examined intraoperatively and 2 false negatives. Three eventual cases of follicular carcinoma were diagnosed after extensive conventional examination. In addition, 128 of the 271 FNAs were diagnosed as colloid nodules and required no further surgical intervention.
Conclusions: This data suggests that even though FNA provides accurate preoperative information, a definitive total thyroidectomy will continue to be based on tissue examination which begins with an intraoperative assessment. FS is most reliable in the diagnosis of papillary carcinoma and colloid nodular disease. The rarity of follicular carcinoma is emphasized by its FS absence in this series. Follicular carcinoma remains a diagnosis dependent on thorough capsular sampling. As long as surgeons understand that follicular carcinoma is a rare disease, follicular lesions are at an increased risk for second surgical procedure.
Category: Head & Neck
Monday, March 9, 2009 1:00 PM
Poster Session II # 178, Monday Afternoon