Utility of intraoperative frozen sections of thyroid tissue in the age of molecular testing

OBJECTIVES

Our study aims to examine the correlation between preoperative ultrasound-guided fine-needle aspiration and intraoperative frozen section and examine the clinical benefit of frozen section in the context of the latest national guidelines on the management of differentiated thyroid cancer.

STUDY DESIGN

A retrospective review of thyroid frozen section from 2012 to2017 at one institution.

SETTING

Tertiary care centre.

PARTICIPANTS/MAIN OUTCOME

Patient demographics, fine-needle aspiration results, molecular testing results, frozen section diagnosis (classified as benign, indeterminate, or malignant), final pathologic diagnosis, initial planned surgery, actual surgery performed, need for additional surgery and complications were recorded. Complications included hematoma formation, hypocalcaemia (requiring readmission, symptomatic, or >24-hour stay post op) and recurrent or superior laryngeal nerve damage.

RESULTS

728 total patients had an intraoperative frozen section performed. A Thy 4/Bethesda V USGFNA diagnosis (n = 55) significantly correlated with a clinically important intraoperative frozen section (n = 17, P < .01). Intraoperative management was changed by the frozen section 53 times (7.2%). Molecular testing was sent on 92 USGFNA specimens, 80 of which were deemed "suspicious." Of the 49 patients whose management was upstaged intraoperatively, 29 (59%) would not necessitate a completion thyroidectomy under the latest UK and ATA guidelines based on final pathology.

CONCLUSION

Intraoperative frozen sections rarely alter the pre-surgical plan and indeed may result in expanded surgery that could have been avoided based on latest UK and US guidelines. Molecular testing of indeterminate fine-needle aspiration results does not appear to predict meaningful intraoperative frozen section results.

Cost effectiveness of intraoperative pathology in the management of indeterminate thyroid nodules

Objective This study aims to determine the cost effectiveness of rapid frozen section (RFS) for indeterminate thyroid nodules. Materials and methods A retrospective chart review was conducted between January 2009 and June 2013 at a tertiary care institution. Main outcomes were number needed to treat, RFS efficacy, and cost-savings of avoiding second completion thyroidectomy. Cost-effectiveness was estimated using 2015 Medicare reimbursement rate. Results Out of 1,114 patients undergoing thyroid surgery, 314 had preoperative AUS/FLUS cytopathology and subsequent thyroid lobectomy with RFS. RFS identified 13 of the 32 patients with malignancy resulting in a total thyroidectomy. 19 of the 29 malignancies not detected by RFS were papillary microcarcinomas. Conclusions Completion thyroidectomy was avoided in 1 out of every 24 patients resulting in cost-savings of $ 80.04 per patient. In the era of outpatient thyroid surgery, intraoperative RFS for indeterminate thyroid nodules is cost-effective.

Thyroid FNAC: Causes of false-positive results

In this paper, we aim to focus on false positive results in the evaluation of thyroid aspirations, covering cystic, inflammatory, follicular and oncocytic lesions, papillary carcinoma, and medullary carcinoma of thyroid. The recently described entity noninvasive follicular thyroid neoplasm with papillary-like nuclear features is also discussed detailing the impact of its introduction on the sensitivity and specificity of thyroid FNA, as well as the use of molecular tests for diagnostics. Medicolegal issues in relation to current practice in English law are also described.

Utility of intraoperative frozen sections for thyroid nodules with prior fine needle aspiration cytology diagnosis

INTRODUCTION

The objective of this study was to evaluate the role of intraoperative frozen section (IFS) in determining the course of surgery in thyroid nodules with a prior fine needle aspiration (FNA) biopsy diagnosis. In addition, reliability of FNA interpretation to guide surgical management without IFS was investigated.

MATERIAL AND METHODS

This is a retrospective study of all patients who had a FNA biopsy, IFS, and final pathology performed on a thyroid nodule over a 9 month period. The extent of surgery at the time of the IFS was recorded. Subsequent change in surgical procedure following the IFS diagnosis was noted in each of the Bethesda diagnostic categories.

RESULTS

55% of the cases were deferred at IFS overall, with 68 and 86% in Bethesda III and IV categories, respectively. Overall, there was a change in management in 6% of cases.

CONCLUSIONS

Our study does not support the use of IFS for nodules with prior FNA interpretation of Bethesda II, III, IV and VI as management was not significantly changed. IFS is of value for nodules with prior FNA diagnosis of Bethesda I for interpretation of nodule, and Bethesda V for planning surgery. A confirmatory diagnosis could not be rendered at IFS for lesions with follicular architecture, which comprised most of the cases in Bethesda III and IV.

Hyalinizing trabecular tumour of the thyroid: fine-needle aspiration cytological diagnosis and correlation with histology

Hyalinizing trabecular tumour (HTT) is a rare thyroid neoplasm of follicular cell origin characterised by a trabecular growth pattern and prominent intratrabecular and intertrabecular hyalinisation. These peculiar histological features allow the prompt recognition of this neoplasm in surgical specimens. However, cytological diagnosis of HTT remains elusive and misleading because of overlapping characteristics with other thyroid tumours, particularly papillary thyroid carcinoma (PTC), medullary thyroid carcinoma (MTC) and the newly described non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Nevertheless, the proper recognition of this neoplasm on preoperative cytological preparations is important to avoid unnecessary overtreatment of this indolent lesion. A thorough review of the literature has revealed that the correct diagnosis of HTT in cytological smears is achieved in only 8% of cases. In a further 6% of cases, diagnostic doubt has been indicated. Sixty percent of published cases of HTT have been misdiagnosed as suggestive, suspicious or positive for PTC. These findings underline the difficulties of a cytological-based diagnosis of such entity. In this article we review the cytomorphological features of HTT and their correlation to histological features to provide the reader with the tools to improve diagnostic performance in the identification of HTT on preoperative cytology.

Effectiveness of fine-needle aspiration cytology in the diagnosis of lateral cervical nonthyroid tumors

Given that the clinical and radiological examinations of lateral cervical masses are not always sufficient for deciding on appropriate management, the cytological examination of the material obtained by fine-needle aspiration might be an efficient tool in the preoperative investigation of these lesions.In this prospective cross-sectional study we evaluated the efficacy and diagnostic accuracy of fine-needle aspiration cytology in the assessment of lateral cervical nonthyroid tumors, by comparing its results with those of histopathology.A total of 58 patients with lateral cervical masses were included. Preoperative cytological results were compared with the histopathologic examination of surgical specimens.Both cytology and histology indicated that malignant tumors outnumbered benign lesions (62% vs 38%), with 88.9% of malignancies presenting in patients aged >50 years, but cytology was less effective at differentiating between benign and nontumor lesions. Cytology had 76.5% specificity and 78.1% sensitivity for identifying malignant lateral cervical lesions, and there was a concordance between the two diagnostic tests (McNemar test, P = 0.17, κ = 0.50, P <0.001).Fine-needle aspiration cytology is a simple, quick, and effective procedure that can aid in the preoperative evaluation of lateral cervical masses by differentiating benign tumors and inflammatory processes from malignancies and thus help in determining a subsequent therapeutic strategy.

Retrospective evaluation of frozen section use for thyroid nodules with a prior fine needle aspiration diagnosis of Bethesda II-VI: The Weill Cornell Medical College experience

Objective

To evaluate the Weill Cornell Medical College (WCMC)/New York Presbyterian Hospital (NYPH) experience with intraoperative frozen (IOF) section in the management of thyroid nodules with a fine needle aspiration (FNA) diagnosis of Bethesda II–VI and to analyze the cost and pathology benefit it provides.

Methods

The surgical and cytopathology files at WCMC/NYPH were searched within the time period of January 2008 to May 2013. A total of 435 thyroid specimens were identified for which both an FNA and subsequent IOF section was performed. The FNA was correlated with the locations of the resected nodule and the nodule frozen for intraoperative diagnosis. The results of the FNA were compared to the IOF section diagnosis and final diagnosis (FD).

Results

Among 435 cases, the FNA diagnosis was Bethesda II: 149 cases, Bethesda III: 170 cases, Bethesda IV: 91 cases, Bethesda V: 19 cases, and Bethesda VI: 6 cases. There were a total of 83 carcinomas identified on FD, which included 69 papillary thyroid carcinomas (PTCs), 12 follicular carcinomas, and 2 poorly differentiated carcinomas. The preoperative FNA diagnosis for these carcinomas was as follows: Bethesda II, 11/149 (7.4%), Bethesda III, 24/170 (14%), Bethesda IV, 26/91 (29%), Bethesda V, 16/19 (84%), and Bethesda VI, 6/6 (100%). IOF section contributed to the diagnosis of malignancy in 16/429 (4%) cases: 1/149 (0.7%) Bethesda II, 5/170 (3%) Bethesda III, 2/91 (1.1%) Bethesda IV, and 8/19 (42%) Bethesda V. The diagnosis of malignancy was confirmed in the 6 Bethesda VI cases by IOF section. There were no false positives on IOF section. IOF had a sensitivity and specificity of 26% and 100%, respectively.

Conclusion

The role of IOF section is limited in the evaluation of thyroid nodules. IOF section is most useful for nodules with an FNA diagnosis of Bethesda V lesions. The diagnosis of follicular variant of PTC remains difficult on frozen section.

A 4-MicroRNA signature can discriminate primary lymphomas from anaplastic carcinomas in thyroid cytology smears

BACKGROUND

Anaplastic thyroid carcinoma (ATC) and primary thyroid lymphoma (PTL) are uncommon tumors of the thyroid gland with several overlapping clinical and pathologic features that may render their differentiation difficult in fine-needle aspiration (FNA) cytology. MicroRNA (miRNA) signatures have been recently reported as useful diagnostic tools applied to cytology specimens.

METHODS

Smears of 23 ATCs, 14 PTLs, and 20 non-neoplastic materials with multinodular goiter (MNG) were retrieved and classified based on their cytologic features and flow cytometric profiles. The ATC-related expression of hsa-miR-26a, hsa-miR-146b, hsa-miR-221, and hsa-miR-222 was quantified using quantitative reverse transcriptase-polymerase chain reaction analysis.

RESULTS

All miRNAs were remarkably up-regulated in ATC samples compared with PTL samples (P < .01). Moreover, expression levels of hsa-miR-146b, hsa-miR-221, and hsa-miR-222 were significantly higher in ATCs than in MNG samples (P < .01). Significant down-regulation of hsa-miR-26a was observed in PTLs compared with MNG samples, whereas hsa-miR-146b was overexpressed. Receiver operating characteristic analysis was used to determine the optimal cutoff for distinguishing ATC from PTL. The estimated receiver operating characteristic thresholds displayed a sensitivity level greater than 0.80 in achieving a diagnosis of PTL, allowing the correct identification of 13 of 14 PTL samples (93%).

CONCLUSIONS

Histotype-specific miRNA signatures can provide new insight into the molecular mechanisms of thyroid carcinogenesis. The tested 4-miRNA signature is a promising diagnostic tool for differentiating ATC from PTL and non-neoplastic MNG, even in the presence of scant material obtained from minimally invasive procedures.

A high-resolution melting protocol for rapid and accurate differential diagnosis of thyroid nodules

A large majority of thyroid nodules are benign, and only 5% have malignant features on cytological examination. Unfortunately, fine-needle aspiration is inconclusive in approximately 30% of all thyroid biopsies, because the cytological features are indeterminate (suspicious for malignancy but not completely diagnostic or nondiagnostic). Wide panels of somatic mutations have been identified in thyroid cancers, and detection of genetic alterations in fine-needle aspirate has been demonstrated to improve diagnostic accuracy. Nevertheless, the relatively high number of genetic targets to be investigated, in comparison with the low percentage of malignant samples, makes the usual diagnostic protocol both time-consuming and expensive. We developed a reliable and sensitive protocol based on high-resolution melting analysis for the rapid screening of mutations of KRAS, HRAS, NRAS, and BRAF oncogenes in thyroid fine-needle aspirations. The entire procedure can be completed in approximately 48 hours, with a dramatic reduction in costs. The proposed protocol was applied to the analysis of 260 consecutive fine-needle aspiration biopsy (FNAB) samples. In 35 of 252 samples, 36 sequence variants were detected for BRAF (17 samples), NRAS (6 samples), HRAS (3 samples), KRAS codon 12 (9 samples), and KRAS codon 61 (1 sample).

The use of the Bethesda terminology in thyroid fine-needle aspiration results in a lower rate of surgery for nonmalignant nodules: a report from a reference center in Turkey

The Bethesda system (BS) for reporting thyroid fine-needle aspiration (FNA), which classifies nodules as nondiagnostic (ND), benign (B), atypia/follicular lesion of undetermined significance (AUS/FLUS), suspicious for follicular neoplasm (SFN/FN), suspicious for malignancy (SFM), or malignant (M), uses clinically valuable management guidelines. The authors employed a similar in-house classification system (IS) for thyroid FNAs, using the categories of ND, B, suspicious follicular cells (SFC), follicular lesion/neoplasm (FL/FN), SFM, and M. The authors compared IS and BS, and assessed the utility of BS in clinical practice. A total of 581 nodules with cytological/histological follow-up were examined and indeterminate lesions by BS were reclassified. The sensitivity and specificity for malignancy using IS were similar to that of BS (77% vs 99%). However, when SFN/FN and SFM were both considered positive, the results for IS and BS were as follows: sensitivity, 85% versus 85%; specificity, 87% versus 94%; and diagnostic accuracy, 86% versus 90%, respectively. Discrepancies between cytological and histological data were evident in 35 cases among all categories of BS except AUS/FLUS. The rate of surgery for nonmalignant nodules was lesser (20% vs 9%) by BS. Among 34 AUS/FLUS cases with follow-up data, hypocellularity was the case in 11 (46%) nonneoplastic and 10 (100%) neoplastic nodules. The use of BS results in a lower rate of surgery for nonmalignant nodules even though patients with borderline cytopathologic features are still encountered. AUS/FLUS category can be separated into subgroups according to the factors causing difficulties in the interpretation. There is a need of accumulation of AUS/FLUS cases to do further evaluations and studies.