Atypia and Follicular Lesions of Undetermined Significance in Subsequent Biopsy Result: What Clinicians Need to Know

Abstract

Atypia and follicular lesions of undetermined significance (AUS/FLUS) is the most controversial category of The Bethesda System. The risk of malignancy (ROM) in this group is estimated as 5–15%, however, the occurrence of two or more subsequent biopsy results with AUS/FLUS diagnosis makes these clinical situations more complex. We evaluated the ROM and prognostic value of aggressive ultrasound (US) features in 342 patients with thyroid nodules (TNs) with subsequent biopsy results of AUS/FLUS. We assessed US features and compared them with the final histopathological diagnosis. Overall, 121 (35.4%) individuals after first AUS/FLUS diagnosis underwent surgery and 221 (64.6%) patients had repeated biopsies. The ROM after first, second, and third biopsies with subsequent AUS/FLUS diagnosis were 7.4%, 18.5%, and 38.4% respectively. We demonstrated significantly higher rates of occurrence of aggressive US features in patients with malignancy (p < 0.0001). The age <55 years old was also a significant risk factor for TC (p = 0.044). Significant associations were found between aggressive US features and malignancy in patients after first diagnosis of AUS/FLUS (p < 0.05). The juxtaposition of US features with the number of biopsy repetitions of TN with consecutive AUS/FLUS diagnoses may simplify the decision-making process in surgical management. Two or three consecutive biopsy results with AUS/FLUS diagnosis increases the ROM.

Assessment of Preoperative TSH Serum Level and Thyroid Cancer Occurrence in Patients with AUS/FLUS Thyroid Nodule Diagnosis

“…We retrospectively analyzed 5024 medical records for patients admitted and surgically treated in the 1st Department and Clinic of General, Gastrointestinal and Endocrine Surgery due to TNs between January 2008 and December 2018 [ 21 ].…”

Hashimoto’s Thyroiditis Does Not Influence the Malignancy Risk in Nodules of Category III in the Bethesda System

“…There are also reports showing some significant differences in malignancy rates observed in patients operated on after a single category III diagnosis, in comparison to those operated on after two such diagnoses; however, they are somewhat contradictory. Some authors found lower malignancy rates in patients operated on directly after a single category III diagnosis: Kaliszewski et al [47]-7.4% vs. 18.5%; Kaya et al [48]-13.3% vs. 27.5%. Others reported increased rates of malignancy in that group of patients: Park et al [49]-77.6% vs. 58.1%; Gweon et al [50]-78.3% vs. 37.2%.…”

Optimization of the Management of Category III Thyroid Nodules Using Repeat FNA and TIRADS

“…It is one of the probable causes of discrepancies between reported results in that respect. Some studies showed a similar frequency of cancers in patients treated surgically after or without rFNA [ 21 , 22 , 23 ]; others indicated an increased rate of malignancy after rFNA, non-significantly [ 8 , 24 , 25 , 26 , 27 , 28 , 29 ] or significantly [ 20 , 30 , 31 , 32 , 33 ] and there are reports that suggested slightly lower malignancy rates in patients undergoing surgery after rFNA in comparison to those treated directly after the diagnosis of category III [ 34 , 35 ].…”

“…Another study did not indicate any difference in the rates of particular categories of rFNA outcomes between nodules with or without cytologic/nuclear atypia [ 5 ]. Many papers that described nodules of category III without their subcategorization showed a marked variation in the rate of rFNA category II results between diagnostic centers, from 36 to 70% [ 9 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 27 , 30 , 31 , 32 , 34 , 36 , 37 ]. These reports also differed in the observed consequences of the category II diagnosis in rFNA.…”