Follicular variant of papillary thyroid carcinoma: comparison of ultrasound-guided core needle biopsy and ultrasound-guided fine needle aspiration in a multicentre study

A simplified four-tier classification for thyroid core needle biopsy

PURPOSE

To propose a simplified histological classification for core-needle biopsy (CNB) of thyroid nodules with four diagnostic categories (DC) and provide the risk of malignancy (ROM) and the expected incidence for each DC. There is no uniform scheme for categorizing CNB specimens, except for a Korean diagnostic classification similar to the Bethesda system for FNAC.

METHODS

Data from a single institution using CNB as a routine diagnostic tool for thyroid nodules. Biopsies were classified as non-diagnostic, benign, follicular tumour (FT) or malignant. The frequency of each DC and the correlation with surgical pathology of nodules undergoing surgery after CNB were evaluated.

RESULTS

Of 6284 CNBs on 5782 nodules [195 (3.1%) non-diagnostic, 5043 (80.3%) benign, 435 (6.9%) FT and 611 (9.7%) malignant], 1914 nodules (33.1%) underwent surgery after 2016 CNBs: 48 non-diagnostic, 1035 benign, 355 FT and 578 malignant. Malignancy was diagnosed after surgery in 11 non-diagnostic (ROM: 22.9%), 23 benign (ROM: 2.2%), 44 FT (ROM: 12.4%, 11.5% excluding low-grade malignancy) and 568 malignant CNBs (ROM: 98.3%, 93.8% excluding low-grade malignancy). Sensitivity and positive predictive value for malignancy of FT or malignant CNB were 94.7% and 65.6%, and for thyroid neoplasm (adenoma or carcinoma) were 93.2% and 92.6%.

CONCLUSIONS

Our diagnostic classification for CNB of thyroid nodules has a high diagnostic accuracy with a low rate of indeterminate categories. This classification, applied in a Western practice, shows a low ROM for nodules classified as follicular tumours, which could be improved with immunohistochemical studies.

Current role of interventional radiology in thyroid nodules

Thyroid nodules are a prevalent health issue in society. Interventional radiological methods are successfully applied for both the diagnosis and treatment of nodules. Diagnostically, a fine-needle aspiration biopsy and a core needle biopsy can be performed to ascertain the benign or malignant nature of a lesion. In recent years, imaging-guided percutaneous treatment methods have become popular in the treatment of thyroid nodules. Aspiration, ablation, and embolization are techniques employed in the treatment process. In this study, we aimed to discuss the current role of interventional radiology in the diagnosis and treatment of thyroid nodules, which occupy an important place in clinical practice.

Is it Possible to Diagnose "Non-Invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features" Preoperatively?

There is no accepted consensus or algorithm for the preoperative diagnosis of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in patients with thyroid nodules. In this study, we evaluated the importance of preoperative neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in the differential diagnosis of NIFTP. Pathology preparations of 209 patients with a follicular variant of papillary thyroid carcinoma (FVPTC) diagnosed after thyroid surgery in a tertiary health center between January 2010 and January 2020 were re-evaluated. Patients were divided into NIFTP and encapsulated follicular variant papillary thyroid carcinoma (EFVPTC) to compare. Of the patients, 58 (27.7%) were NIFTP, and 151 (72.3%) were EFVPTC. There was no statistically significant difference in terms of age (p = 0.46), tumor size (p = 0.51), gender (p = 0.48), and surgical technique (p = 0.78) between the groups. The probability of the neutrophil-to-lymphocyte ratio (NLR) > 2 is more common in the EFVPTC group. It was statistically significant that the NIFTP group was 1.96 times more likely to have NLR > 2 (OR: 1.96, 95% CI: 1.06-3.63) (p < 0.05). However, there was no risk difference between the groups in terms of the platelet-to-lymphocyte ratio (PLR) (OR: 0.76, 95% CI: 0.41-1.43) (p > 0.05). The diagnosis of NIFTP should be kept in mind in the evaluation of patients whose thyroid fine-needle aspiration (FNA) biopsy results are in the intermediate group. NIFTP exhibits better prognostic findings than classic thyroid papillary cancer and EFVPTC. Therefore, preoperative diagnosis of NIFTP in line with laboratory, ultrasonography, and FNA findings will save the patient from unnecessary overtreatment.

Limitations of fine-needle aspiration and core needle biopsies in the diagnosis of tall cell variant of papillary thyroid carcinoma

BACKGROUND

The tall cell variant papillary thyroid carcinoma (TCV-PTC) shows aggressive behaviour. Thus far, the diagnosis of TCV-PTC can only be confirmed using the postoperative specimen. This study aims to evaluate whether fine-needle aspiration (FNA) or core needle biopsy (CNB) could diagnose TCV-PTC preoperatively.

METHODS

This is a retrospective cohort study. We included adult patients diagnosed with TCV-PTC or PTC with tall cell features (TCF) at final surgical pathology between January 2015 and December 2018. Preoperative histology was reviewed for six cytomorphologic features suggesting TCV-PTC in FNA or the percentage of tall cells in the CNB specimen. The postoperative pathology was also reviewed to confirm the percentage of tall cells.

RESULTS

A total of 119 patients were included in this study; 35 (29%) patients with PTC with TCF served as controls. The most frequent cytomorphological feature in FNA samples of TCV-PTC was tall columnar cells, including single tombstone-like cells (70%). Among 43 TCV-PTC evaluated by FNA, 3 FNA (7%) revealed the absence of any of the six cytomorphologic features suggesting TCV-PTC. When we defined 30% of tall cells in CNB specimens as a cutoff suggesting TCV-PTC, only 16 (41%) TCV-PTCs could be preoperatively detected, and 3 (7%) TCV-PTCs did not have any tall cells. The proportion of tall cells was not associated with the postoperative percentage of tall cells.

CONCLUSION

Both cytomorphologic features in FNA and the percentage of tall cells in CNB present limitations for use as accurate preoperative diagnostic tools of TCV-PTC.

Core needle biopsy and ultrasonography are superior to fine needle aspiration in the management of follicular variant papillary thyroid carcinomas

PURPOSE

Follicular variant papillary thyroid carcinoma (FVPTC) is a problematic entity. FVPTCs are often misdiagnosed by the standard fine needle aspiration (FNA); in addition, FVPTCs represent a mixed group of tumors with two biologically distinct subtypes: The indolent encapsulated FVPTC and the aggressive infiltrative FVPTC. Recent changes in guidelines suggests that FVPTC management may be improved if subtypes can be determined preoperatively. Preoperative assays, FNA, core needle biopsy (CNB), and ultrasonography (US) were compared for their ability to identify and subtype FVPTCs to determine the most appropriate test to manage FVPTCs.

METHODS

The preoperative assays and clinicopathologic variables of 255 resected FVPTCs cases at Samsung Medical Center between 2012 and 2016 were retrospectively evaluated.

RESULTS

CNB had the overall best ability to manage FVPTCs with the highest rate of diagnosis indicating surgery, lowest rate of inconclusive results, high sensitivity (88.9%), specificity (87.7%), negative predictive value (97.0%), diagnostic odds ratio (DOR; 56.9), and excellent predictive ability (AUC 0.906) for differentiating FVPTC subtypes. US had a moderate DOR (12.8), good predictive ability (AUC 0.802), high sensitivity (75.0%) and specificity (81.0%). CNB and US both had significantly higher accuracy for discriminating FVPTC subtypes than FNA (AUC 0.908 and 0.877 > 0.671; p < 0.05). The excellent performance of CNB could be attributed to distinct histologic differences between FVPTC subtypes.

CONCLUSION

CNB and US had superior performance to FNA in the identification and subtyping of FVPTC. In institutions with skilled and experienced operators, CNB is the preferred method for evaluating possible FVPTC lesions.

The relationship of thyroid nodule size on malignancy risk according to histological type of thyroid cancer

Background

Although several studies have examined the value of thyroid nodule size as a malignancy predictor, the results are conflicting.

Purpose

To investigate the relationship between nodule size and malignancy risk and to evaluate the impact of nodule size on the false-negative rate of fine needle aspiration or core needle biopsy according to the histological type of thyroid cancer.

Material and Methods

From January 2013 to December 2013, 3970 thyroid nodules that underwent ultrasound-guided fine needle aspiration or core needle biopsy were retrospectively reviewed. We assessed the relationship between nodule size and malignancy risk according to histological type of thyroid cancer. In addition, we compared the false-negative rate by thyroid nodule size category.

Results

Of 3970 thyroid nodules, 1170 nodules were malignant. For papillary thyroid carcinoma, nodule size was inversely related to malignancy risk, whereas in nodules of follicular carcinoma and follicular variant papillary thyroid carcinoma, nodule size was positively related to malignancy risk ( P < 0.001). The false-negative rate tended to increase as nodule size increased ( P = 0.002) for all nodules and the overall false-negative rate was 2.3%.

Conclusion

Overall, nodule size does not correlate with risk of malignancy, but the relationship between nodule size and malignancy risk depends on the histological type of thyroid cancer.

Sonographic features of follicular variant of papillary thyroid carcinoma (FV-PTC) and diagnostic performance of the 2017 ACR TI-RADS in FV-PTC

PURPOSE

To find the sonographic features of follicular variant of papillary thyroid carcinoma (FV-PTC) and evaluate the diagnostic performance of 2017 ACR TI-RADS in FV-PTC.

METHODS

From June 2017 to June 2019, 104 FV-PTC patients (106 nodules) and 337 classic papillary thyroid carcinoma (C-PTC) patients (343 nodules) with both sonograms and pathologic results were included. Sonographic features of FV-PTC and C-PTC were evaluated and compared, and 2017 ACR TI-RADS scores and levels were calculated.

RESULTS

Pathologically, the incidence of Hashimoto's thyroiditis and extrathyroidal extension was higher in the FV-PTC group. Most of both the FV-PTC and C-PTC groups were diagnosed as PTC or suspicious PTC by fine-needle aspiration biopsy (FNAB). FV-PTC tended to be isoechoic, while most nodules of C-PTC were hypoechoic or very hypoechoic. Compared with C-PTC, FV-PTC had lower percentages of a taller-than-wide shape (11.3% vs. 46.6%) and lobulated or irregular margin (33.0% vs. 61.8%), and a higher percentage of extrathyroidal extension (20.8% vs. 8.2%). FV-PTC featured macrocalcifications, whereas punctate echogenic foci were more frequently seen in the C-PTC group. Other characteristic US appearances of FV-PTC included uneven hypoechoic halo and peripheral vascularity. The mean TI-RADS score of FV-PTC cases was lower in the FV-PTC group, 11.3%, 44.3%, and 42.5% of which were categorized as TI-RADS 3, 4, and 5, respectively.

CONCLUSIONS

FV-PTC features isoechoic appearance, macrocalcifications, uneven hypoechoic halo, and peripheral vascularity on US, with lower incidences of microcalcifications and taller-than-wide shape, and tends to have lower TI-RADS scores and levels. For the nodules categorized as TI-RADS 3 or 4, the FNAB criteria should be broaden when these nodules have FV-PTC US features.

Evaluation of surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm

Background

The objective of this study was to evaluate the surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm and to explore whether it is reasonable generally to ignore the diagnosis and treatment of thyroid nodules and thyroid carcinoma <1 cm in wide areas of China.

Methods

A retrospective observational study included all first-time thyroid surgery patients between January 2005 and December 2016 of the First Affiliated Hospital of Harbin Medical University. All patients were divided into two groups (group A: <1 cm, group B: ≥1 cm) according to the maximum diameter of the nodules and demographics, surgery procedure, pathology, postoperative complications, morbidity, and mortality were analyzed.

Results

A total of 6,317 patients were reviewed and 3,424 (54.20%) of them were malignant; 2,128 patients in group A and 4,189 in group B. Patients in group A had better pathological diagnosis, inferior extent of lymph node metastasis, less surgical complexity, fewer postoperative complications, and longer disease-free survival (DFS).

Conclusions

Thyroid operations were safer and involved fewer postoperative complications when thyroid nodules were <1 cm and patients who were diagnosed with malignant thyroid disease had superior prognoses. Underdeveloped regions of China should diagnose and treat thyroid nodules <1 cm early.

Does Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features (NIFTP) Have a Unique Molecular Profile?

OBJECTIVES

Recognizing preoperative characteristics of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is important for clinical management. Therefore, we assessed presurgical NIFTP molecular profiles using fine-needle aspiration (FNA) material.

METHODS

Presurgical FNA reports of 39 surgically confirmed NIFTP cases from January 2013 through May 2017 were assessed for Afirma and ThyroSeq results.

RESULTS

Twenty-one of 39 NIFTP nodules were preoperatively tested with Afirma with two benign and 19 suspicious results. Twenty-seven of 39 nodules were tested with ThyroSeq (nine of 39 had both Afirma and Thyroseq): 18 (67%) had RAS mutations (13 NRAS, four HRAS, one KRAS), and three of 18 had multiple alterations (NRAS + TP53, n = 1; NRAS + PTEN, n = 2). BRAF T599_R603 + EIF1AX mutation (n = 1), PTEN mutation (n = 1), MET overexpression (n = 1), PAX8/PPARG fusion (n = 3), and THADA/IGF2BP3 fusion (n = 3) comprised the remainder.

CONCLUSIONS

NIFTP cases most commonly displayed suspicious Afirma results and RAS mutations on ThyroSeq, lacking aggressive/BRAF-V600E-like mutations. While NIFTP remains a surgical entity, the lack of aggressive/BRAF-V600E-like mutations can aid in determining the extent of surgery.

TIRADS score is of limited clinical value for risk stratification of indeterminate cytological results

CONTEXT

Thyroid nodules with cytological indeterminate results represent a daily and recurrent issue for patient management.

OBJECTIVE

The primary aim of our study was to determine if TIRADS (Thyroid Imaging Reporting and Data System) could be used to stratify the malignancy risk of these nodules and to help in their clinical management. Secondary objective was to estimate if this risk stratification would change after reclassification of encapsulated non-invasive follicular variant of papillary carcinomas (FVPTC) as non-invasive follicular thyroid neoplasm (NIFTP).

PATIENTS AND METHODS

Single-center retrospective study of a cohort of 602 patients who were referred for ultrasound-guided fine-needle aspiration from January 2010 to December 2016 with an indeterminate cytological result and in whom histological results after surgery were available. TIRADS score was prospectively determined for all patients included. Nodules that had been classified as FVPTC were submitted to a rereading of histological report and reclassified as NIFTP when judged relevant. A table of malignancy risk crossing Bethesda and TIRADS results was built before and after this reclassification.

RESULTS

The study included 602 cytologically indeterminate nodules. TIRADS score was positively correlated with the malignancy rate (P < 0.0001). Risk stratification with TIRADS was significant only in Bethesda V nodules (P = 0.0004). However, the risk of malignancy in this Bethesda V category was always above 45%, whatever the TIRADS score.

CONCLUSION

For a clinician facing an indeterminate cytological result for a thyroid nodule, return to TIRADS score is of limited value in most conditions to rule in or rule out malignancy and to guide subsequent management of patients.

Statement and Recommendations on Interventional Ultrasound as a Thyroid Diagnostic and Treatment Procedure

The recently published guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on interventional ultrasound (INVUS)-guided procedures summarize the intended interdisciplinary and multiprofessional approach. Herewith, we report on recommendations for interventional procedures for diagnosis and treatment of the thyroid gland.

Does noninvasive follicular thyroid neoplasm with papillary-like nuclear features have distinctive features on sonography?

BACKGROUND

The noninvasive encapsulated follicular variant of papillary carcinoma (nEFVPTC) has recently been reclassified to "noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)," removing this entity from the malignant category. This re-categorization has had major implications for clinical management. NIFTP has overlapping cytohistologic features with papillary thyroid carcinoma (PTC) and with follicular adenomas (FA), but sonographic data comparing NIFTP to PTC and FA is lacking. Our study examines the sonographic features of NIFTP as compared with PTC and FA.

METHODS

Ultrasound scans and Doppler blood flow from subjects who had pre-surgical sonograms and fine needle aspiration biopsies with final surgical pathology diagnoses of NIFTP/nEFVPTC, classical PTC, and FA between 01/2013-08/2016 were assessed. Sonographic and Doppler features as well as Bethesda System (TBS) diagnoses were recorded and analyzed.

RESULTS

40 NIFTP, 58 classical PTC, and 23 FA cases were included. The most common NIFTP pre-surgical TBS cytology diagnosis was Atypia of Undetermined Significance (AUS/FLUS) (40%). NIFTP cases predominantly displayed wider-than-tall shape (100%), smooth borders (75%), occurrence in multinodular glands (82.5%), heterogeneous echogenicity (50%), both perinodular and intranodular Doppler flow patterns (70%), minimal Doppler flow grade (62.5%), and no calcifications (90%).

CONCLUSIONS

Our study demonstrates that NIFTP, PTC, and FA display several distinguishing and overlapping sonographic and Doppler features. Sonographic features appear to complement cytology findings and may help raise pre-operative concern for NIFTP in the proper clinical setting, potentially leading to a more conservative management approach.