The role of ultrasound findings in the management of thyroid nodules with atypia or follicular lesions of undetermined significance

Abstract

BackgroundAtypia or follicular lesions of undetermined significance (AUS/FLUS) is a broad cytological category in the Bethesda system for classifying thyroid cytology. This study investigated the diagnostic accuracy of ultrasound (US) analysis of thyroid nodules with AUS/FLUS. Patients and MethodsOf 5062 subjects with nodules subjected to fine-needle aspiration cytology (FNACs) at our institution from January 2010 through May 2012, 383 met the Bethesda criteria for AUS/FLUS. After excluding subjects who had a history of thyroid cancer, who only underwent repeat FNA or who underwent no further examinations, we selected 249 subjects who had subsequently undergone a core-needle biopsy and/or surgery. Of these, 100 were found to have malignant nodules (402%), 122 had benign nodules (49%), and 27 had nodules with indeterminate status (108%). We compared specific US parameters, including size, location, content, shape, margin, echogenicity, echotexture and calcification across these subject groups. ResultsMultivariate analysis revealed that malignancy was associated with taller-than-wide shape (TDW) (OR=843, P= 0002), ill-defined margin (OR=323, P=0002) and marked hypoechogenicity. (OR=361, P=0001). The specificity and positive predictive values of TDW were 98% and 906%,respectively. The specificity and positive predictive values of TDW and marked hypoechogenicity' were both 100%. ConclusionUS findings play a complementary role in the diagnosis of thyroid nodules with AUS/FLUS. In case of highly suspicious US findings such as TDW and marked hypoechogenicity', could be very helpful in the diagnosis of malignancy.