Institution-specific risk of papillary thyroid carcinoma in atypia/follicular lesion of undetermined significance.
The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) is used in surgical decision-making according to malignancy risk in each category. Malignancy risk in atypia/follicular lesion of undetermined significance (AUS/FLUS) is estimated in BSRTC to be 5% to 15%, but institutional data have varied widely.



We conducted a post-BSRTC 4-year retrospective analysis of index thyroid nodule cytology and histopathology in an academic head and neck endocrine surgery setting.



Of 2939 thyroid cytology reports from 1944 patients, the most advanced BSRTC category was AUS/FLUS in 233 patients (12.0%) of which 187 went to thyroidectomy. In AUS/FLUS, the upper and lower boundary estimates of the malignancy rate were 46% and 37%, accordingly. The malignancy rate did not vary significantly by cytopathologist or cytopathologic features.



Malignancy rates in AUS/FLUS vary by institution from 6% to 46%. Given the subjective nature of thyroid cytopathology and interpretation of the BSRTC categories, guidelines should encourage the use of institution-specific data on malignancy risk in treatment decisions. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1210-E1215, 2016.
Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada.
Jonathan M
JM
Bernstein
Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada.
Manish
M
Shah
Department of Laboratory Medicine and Pathobiology, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada.
Christina
C
MacMillan
Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada.
Jeremy L
JL
Freeman
D018263:Adenocarcinoma, Follicular; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000175:diagnosis*; D000066491:Clinical Decision-Making; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D018570:Risk Assessment; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis*; D016606:Thyroid Nodule / Q000145:classification / Q000473:pathology*; D013965:Thyroidectomy
Bethesda System for Reporting Thyroid Cytopathology (BSRTC); National Cancer Institute (NCI); atypia of undetermined significance (AUS); follicular lesion of undetermined significance (FLUS); malignancy risk; thyroid cancer