BACKGROUND: Molecular testing of thyroid nodules is increasingly being utilized to guide clinical management decisions. RAS mutations are the most frequent mutations detected in the context of an indeterminate fine needle aspiration (FNA) diagnosis. The term noninvasive @entity259 with papillary-like nuclear features (NIFTP) was recently introduced to promote conservative management of @entity5 previously classified as noninvasive follicular variant of @entity3557 (FVPTC). This change in terminology was based on the indolent clinical behavior of these @entity5 and their molecular profile, which includes frequent RAS mutations. The aim of this study was to determine the percentage of RAS-mutant " @entity189 " that would now be classified as NIFTPs. METHODS: We searched for cases with known activating RAS mutations in a database of 199 @entity259 that underwent molecular characterization as part of Profile:Oncopanel between 7/2013 and 7/2015. Cases of FVPTC were re-reviewed to identify @entity5 that now would be categorized as NIFTP. Preceding FNA diagnoses were recorded, and cases with an indeterminate FNA result (defined as a diagnosis of atypia/follicular lesion of undetermined significance, suspicious for @entity5 , or suspicious for @entity5 ) were identified. RESULTS: We identified 27 RAS-mutant @entity259 . Fifteen (56%) cases had an @entity8497 mutation, 9 (33%) had an @entity8498 mutation, and 3 (11%) had a @entity984 mutation. Twenty-four (89%) cases had a preceding FNA, 19 (79%) of which had an indeterminate FNA diagnosis. The surgical resection specimen demonstrated FVPTC in 20 (74%) cases, classical type PTC in 2 (7%), solid variant of PTC in 1 (4%), and @entity259 in 4 (15%). Of the 20 FVPTCs, 16 (80%) would now be classified as NIFTP. NIFTPs accounted for 59% of @entity189 overall and 63% of @entity189 with a prior indeterminate FNA diagnosis. CONCLUSION: NIFTPs accounted for over half of RAS-mutant " @entity189 " in our cohort. In cases where clinical and sonographic data support a low-risk phenotype, these results suggest that a lobectomy should be considered as the initial surgical approach for a nodule with an indeterminate FNA diagnosis and a RAS mutation.

NIFTP Accounts for Over XXXX " Harboring RAS Mutations.

@entity3557 :: ('MESH:C536915', 'Disease') :: ['papillary thyroid carcinoma'] @entity5 :: ('MESH:D009369', 'Disease') :: ['follicular neoplasm', 'malignancy', 'tumors'] @entity8498 :: ('3265', 'Gene') :: ['HRAS'] @entity984 :: ('3845', 'Gene') :: ['KRAS'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinomas', 'RAS-mutant carcinomas'] @entity8497 :: ('4893', 'Gene') :: ['NRAS'] @entity259 :: ('MESH:D013964', 'Disease') :: ['follicular thyroid neoplasm', 'thyroid tumors', 'thyroid carcinomas', 'follicular thyroid carcinoma']
@entity189 :: (MESH:D002277,Disease) :: ['Half of "Carcinomas']
