Fine-needle aspirates of thyroid microcarcinoma

Abstract

Precis:In our experience, indeterminate diagnoses (FLUS+FN+SM) accounted for the majority (60%) of preoperative FNAs for incidental microcarcinoma (size ≤0.5 cm) when compared to 27% for those of non-incidental microcarcinoma (size >0.5 cm and ≤1 cm) (p<0.05, chi-square test). ABSTRACT: INTRODUCTION:Widespread use of ultrasound allows for detection of smaller thyroid nodules and preoperative evaluation with fine-needle aspiration (FNA). Both incidental and non-incidental microcarcinoma can be found, leading to uncertainty with clinical management. MATERIALS AND METHODS:A retrospective analysis of thyroid FNAs performed at our institution was conducted for the 5year period from 2010 to 2014. Aspirates were categorized using the Bethesda System for Reporting Thyroid Cytopathology. Cytologic diagnoses were then correlated with final histopathology. Among samples with malignancy on surgical resection, nodules were stratified by size. RESULTS:A total of 2531 thyroid FNAs were identified. 587 samples had histologic correlation, and 259 malignancies were reported. They were separated into nodules >1 cm (n=144, 56%) and ≤1 cm (n=115, 44%). Microcarcinoma was further subdivided into incidental (size ≤0.5 cm, n=55, 48%) and non-incidental (size >0.5 cm and ≤1 cm, n=60, 52%). The preoperative cytologic diagnoses for incidental microcarcinoma were: benign (B, n=11, 20%), follicular lesion of undetermined significance (FLUS, n=15, 27%), follicular neoplasm (FN, n=11, 20%), suspicious for malignancy (SM, n=7, 13%), malignant (M, n=8, 15%), and non-diagnostic (ND, n=3, 5%). The FNA categories for non-incidental microcarcinoma were: B (n=13, 22%), FLUS (n=3, 5%), FN (n=3, 5%), SM (n=10, 17%), M (n=29, 48%) and ND (n=2, 3%). CONCLUSIONS:Incidental microcarcinoma is not an uncommon entity, making up 21% (55/259) of malignant nodules on thyroidectomy. Indeterminate diagnoses (FLUS+FN+SM) accounted for the majority

Outcomes of active surveillance of EU-TIRADS 5 thyroid nodules

“…While some authors advocate that FNAB should precede the decision of active surveillance of nodules ≤ 10 mm (11), our study shows that FNAB is frequently caught in default in small nodules. This is consistent with previous reports showing rates as high as 60% of indeterminate cytological diagnosis (Bethesda III, IV, V) for malignant thyroid nodules under 5 mm and 27% for those between 5 and 10 mm have been reported (12). It has also been shown that there are up to 17.8% of non-diagnostic specimens (Bethesda I) in nodules ≤ 10 mm (13), and up to 35.6% in non-palpable nodules under 8 mm (14).…”

“…Indeed, some authors such as P W Rosario et al (11) consider that FNAB should precede the decision of AS of nodules ≤ 10 mm, to avoid repeating US if benign, to prevent the psychological stress of having a presumptive diagnosis of 'cancer' or of a 'nodule with highly suspicious features', or to detect rare cytological variants of cancer that are not candidates for active surveillance. However, rates of non-diagnostic and indeterminate cytological results in sub-centimeter nodules can be as high as 35.6 and 60%, respectively (12,13,14). These suspicious nodules, with no evidence of malignancy, were excluded from previous studies, thus introducing a potential recruitment bias.…”