Frozen section analysis in the post-Bethesda era.
The utility of frozen section (FS) for indeterminate thyroid nodules is controversial. In 2009, the Bethesda System for Reporting Thyroid Cytopathology was established to further subcategorize indeterminate fine-needle aspiration results (follicular lesions, FL) into Bethesda category 3 (BC3) and Bethesda category 4 (BC4). We hypothesize that FS will have less utility in the evaluation of BC3 lesions when compared to BC4.



A total of 479 patients who underwent thyroid lobectomy from January 2008 to July 2014 were retrospectively reviewed. Patients without appropriate Bethesda categorization were excluded. A total of 135 patients (65 FL, 45 BC3, 25 BC4) comprised the study groups. The sensitivity and specificity of FS within these three categories were determined.



In the FL group, 6 of 65 patients were found to have thyroid cancer. Three were identified on frozen section (FS) resulting in a sensitivity and specificity of 50% and 100%, respectively. Thus, FS changed the operation in 3 of 65 cases (4.6%). In the BC3 group, 5 of 45 patients were found to have cancer. One was identified on FS resulting in a sensitivity and specificity of 20% and 100%, respectively. Thus, FS changed the operation in 1 of 45 patients (2.2%). In the BC4 group, 4 of 25 patients were found to have cancer. Two were identified on FS resulting in a sensitivity and specificity of 50% and 100% respectively. Thus, FS changed the operation in 2 of 25 patients (8%).



There is improved utility of FS in BC 4 patients as 8% avoided reoperation. However, this benefit hinges on surgeon practice regarding the management of differentiated thyroid cancer >1 cm and <4 cm.
Department of Surgery, University of Michigan, Ann Arbor, Michigan. Electronic address: tcotton@usasurg.org.
Travis M
TM
Cotton
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
Jing
J
Xin
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
John
J
Sandyhya
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
Roy
R
Lirov
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
Barbara S
BS
Miller
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
Mark S
MS
Cohen
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
Paul G
PG
Gauger
Department of Surgery, University of Michigan, Ann Arbor, Michigan.
David T
DT
Hughes
D018263:Adenocarcinoma, Follicular / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D002291:Carcinoma, Papillary; D003937:Diagnosis, Differential; D005260:Female; D005629:Frozen Sections / Q000592:standards*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy
Bethesda System for Reporting thyroid cytopathology; Follicular lesions of undetermined significance; Indeterminate thyroid lesion; Suspicious for follicular neoplasm; Thyroid frozen section