An Indeterminate for Malignancy FNA Report Does Not Increase the Surgical Risk of Incidental Thyroid Carcinoma

Abstract

Incidental thyroid carcinomas (ITCs) are a fairly frequent finding in daily routine practice, with papillary thyroid microcarcinoma being the most frequent entity. In our work, we isolated incidental cases arising in thyroids removed for other cytologically indeterminate and histologically benign nodules. We retrospectively retrieved cases with available thyroid Fine Needle Aspiration (FNA, 3270 cases), selecting those with an indeterminate cytological diagnosis (Bethesda classes III–IV, 652 cases). Subsequently, we restricted the analysis to surgically treated patients (163 cases) finding an incidental thyroid carcinoma in 22 of them. We found a 13.5% ITC rate, with ITCs representing 46.8% of all cancer histologically diagnosed in this indeterminate setting. Patients received a cytological diagnosis of Bethesda class III and IV in 41% and 59% of cases, respectively. All ITC cases turned out to be papillary thyroid microcarcinomas; 36% of cases were multifocal, with foci bilaterally detected in 50% of cases. We found an overall ITC rate concordant with the literature and with our previous findings. The assignment of an indeterminate category to FNA did not increase the risk of ITCs in our cohort. Rather, a strong statistical significance (p < 0.01) was found comparing the larger size of nodules that underwent FNA and the smaller size of their corresponding ITC nodule.

The Complex Cyto-Molecular Landscape of Thyroid Nodules in Pediatrics

“…According to Baran et al, low- and high-risk mutations account for approximately 50% and 30% of malignant pediatric nodules, respectively, while the remaining cases harbor relatively uncommon variants (APC, BLM, PPM1D mutations, FGFR1 rearrangements) which require further investigation [ 46 ]. In addition, they observed a correlation between the Bethesda category and the presence of high-risk genetic alterations, opening the possibility of creating an effective cytological and molecular combined algorithm of risk classification, as previously performed with ultrasound and FNA [ 1 , 19 , 46 ]. DICER1 mutations seem to correlate with the macrofollicular variant of FTC, in which have been found in up to 50% of cases, and seem to be involved in the progression from FTC to PDTC [ 10 ].…”

“…Nonetheless, prophylactic surgery remains recommended in children harboring RET mutations (MEN syndromes) and at risk of medullary thyroid carcinoma (MTC) onset, with the timing of surgery determined by the known progression risk of every specific mutated codon [ 2 ]. However, the US-based surveillance of nodule growth did not prove reliable in assessing the malignant nature of children’s lesions, given the particularly slow growth of many thyroid cancers [ 1 , 14 ].…”

“…To further expand the information to articles published before the censoring period, a secondary search of the literature was manually conducted from the references of our primary search, including papers by the application of the same inclusion and exclusion criteria. Articles satisfying the following inclusion criteria were included in our review (regardless of the study design): [ 1 ] study was written in English; [ 2 ] the full article could be obtained. Articles satisfying the following exclusion criteria were excluded from our review: [ 1 ] study was written in a non-English language; [ 2 ] the full article was not available; [ 3 ] study was not related to thyroid FNA in pediatrics; [ 4 ] study was not published in a peer-reviewed journal.…”

“…Articles satisfying the following inclusion criteria were included in our review (regardless of the study design): [ 1 ] study was written in English; [ 2 ] the full article could be obtained. Articles satisfying the following exclusion criteria were excluded from our review: [ 1 ] study was written in a non-English language; [ 2 ] the full article was not available; [ 3 ] study was not related to thyroid FNA in pediatrics; [ 4 ] study was not published in a peer-reviewed journal. Literature review and data extraction were conducted independently by two reviewers (D.S.…”

“…In recent years, the overall incidence of thyroid malignancy has increased mainly due to significant improvements in high-resolution ultrasonography (US)-guided fine-needle aspiration (FNA), leading to earlier cancer detection [ 1 ]. US is a non-invasive imaging method that is suitable for thyroid evaluation and is well accepted by patients of all ages, whereas FNA is considered the best method for evaluating thyroid nodules to minimize unnecessary surgeries or establish the proper extent of surgery [ 2 , 3 ].…”