Malignancy Rate in Thyroid Nodules with Atypia or Follicular Lesion of Undetermined Significance

Abstract

Introduction Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is one of the six diagnostic categories of the Bethesda System for Reporting Thyroid Cytopathology. The prevalence of malignancy among Bethesda category III cytology is variable, ranging from 5% to 37% in the literature. Objective To determine the rate of malignancy in thyroid nodules reported as Bethesda category III. Methods A total of 495 patients underwent surgical intervention for thyroid nodules from January 2015 to December 2017. The present study included 81 cases reported as Bethesda category III, and their medical records were reviewed. Results Out of 495 fine-needle aspiration cytology samples, 81 (16.4%) samples were labeled as AUS/FLUS. Among these 81 patients, the mean age was 43.0 years (± 13.9), with only 11 (14%) patients older than 55 years of age. Most of our patients were female (n = 69; 85.2%), and the rest were male. The rate of malignancy based on the final histology was of 33.3% (n = 27). The majority were 17 cases (21%) of papillary carcinoma, followed by follicular carcinoma (n = 6) (7.4%). Conclusion The risk of malignancy can be higher than it is commonly believed, and guidelines should be based on the data from the institutions themselves for a better assessment of the outcomes.

Malignancy Rates of Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS) Cases: a Tertiary Center Study

“…In our study there were no NIFTP cases diagnosed after the NIFTP entity was introduced in 2016 or in former cases which evaluated respectively. If AUS/FLUS cases underwent surgery the most common malignancy was PTC followed by FC in histopathological examination (15,16). Similarly, in our study 90.9% (10/11) of tumors were PTC.…”

“…However, studies have observed higher malignancy rate in different clinical settings and recommend reconsideration of malignancy rate and management guidelines in this category (12)(13)(14). In a study which determined the rate of malignancy in 81 thyroid nodules reported as AUS/FLUS, ROM was found 33.3% (15). On the other hand, a study from India ROM of AUS/FLUS cases was 66.7% (16).…”

Risk Stratification of Thyroid Nodules with Bethesda III Category: The Experience of a Territorial Healthcare Hospital

“…The present study identified the PTC follicular variant (39%) and PTC classical (27%) as the commonest forms of thyroid cancer in the study population. Earlier research reported findings that corroborated this result and showed that generally, PTC is the commonest type of thyroid cancer [28]. In fact, 80% of all thyroid malignancies and higher than 90% of the differentiated thyroid cancers are of the PTC variety.…”

The Correlation of Age with Prognosis of Atypia of Undetermined Significance and Follicular Lesion of Undetermined Significance in Thyroid Nodules

“… 3–6 The prevalence of malignancy within this category ranges from 5% to 37%. 7 , 8 Some other studies report an even higher malignancy rate, up to 55%, suggesting diagnostic and simultaneous therapeutic lobectomy in cases of AUS/FLUS diagnosis. 9 , 10 The implied risk of malignancy of AUS/FLUS assessed and presented in 2009 in TBSRTC was 5–15%.…”