How do liquid-based preparations of thyroid fine-needle aspiration compare with conventional smears? An analysis of 5475 specimens

Diagnostic values of SurePath liquid-based cytology versus conventional smear in thyroid aspiration samples: A 13-year experience at a single institution

BACKGROUND

Fine needle aspiration cytology (FNAC) is the most useful tool in the diagnosis of thyroid nodules. Liquid-based cytology (LBC) is replacing the conventional smear (CS) for evaluation of thyroid FNAC. In our institution, thyroid FNAC preparation was changed from CS to LBC SurePath in July 2016. This study aimed to compare the diagnostic value of SurePath with that of CS in thyroid lesions.

METHODS

A total of 35,406 samples of thyroid FNAC (11,438 CS and 23,968 SurePath), collected from January 2010 to December 2022, were included in this study. We also examined the malignant rate using the surgical pathology diagnosis as the gold standard.

RESULTS

The distribution of TBSRTC cytological categories was equivalent between CS and SurePath. The rate of nondiagnostic/unsatisfactory category was higher in CS compared to SurePath (43.4% vs. 22.3%; p < .05). After routine use of SurePath, the surgical resection rate was reduced from 12.0% to 8.6% (p < .05) and the malignant rate increased from 32.2% to 41.5% (p < .05). The sensitivities of CS and SurePath were 71.0% and 82.0%, respectively, and the specificities were 99.0% and 97.3%, respectively, whereas the positive predictive values were 97.8% and 96.8%, respectively, and the negative predictive values were 85.0% and 84.6%, respectively. Diagnostic accuracy of CS and SurePath were 88.5% and 89.7% respectively.

CONCLUSION

SurePath can increase the sample adequacy, increase the sensitivity and reduce the workload and avoid unnecessary surgeries with similar accuracy to CS.

Advances in diagnostic liquid-based cytology

Liquid-based cytology (LBC) has changed the landscape of gynaecological cytology. A growing demand exists for LBC in diagnostic cytology, particularly for ancillary testing, such as immunocytochemistry and molecular testing. Ancillary testing solely based on conventional preparation (CP) methods remains challenging. Recently, the increased demand for specialist testing and minimally invasive techniques, such as endoscopic ultrasonography fine-needle aspiration, to obtain cellular samples has led to an increasing demand for ancillary testing on cytology LBC supernatant, slides and cell block (CB). This facilitates the diagnosis and prognosis in cytology samples enabling personalized treatment. An understanding of the history and future prospects of LBC is crucial for its application in routine diagnostics by cytopathologists and cytotechnologists. In this review, we initiated an internet search using the keyword 'liquid-based cytology', and we conducted a literature review to discuss the usefulness of combined diagnosis of LBC and CP, immunocytochemistry and molecular testing and assessed the quality of nucleic acids in diagnostic LBC. High-quality and cell-rich diagnostic LBC surpassed the CP method alone in terms of reliability and versatility of ancillary testing in cytological diagnosis. Conclusively, diagnostic LBC lends itself to various new technologies and is expected to continue evolving with innovations in the future.

Process improvement in thyroid fine needle aspiration: Standardizing number of smears for enhanced adequacy and diagnosis

Fine-needle aspiration (FNA) is a safe, cost-effective diagnostic procedure used in the evaluation of thyroid nodules. The number of thyroid FNAs has dramatically increased over the past few years. In the absence of standardized procedures regarding the number of needle passes needed for diagnosis and the lack of clarity on the use of conventional smears (CS) versus liquid-based preparations (LBP), the demand of thyroid FNAs has led to increased workload on cytology laboratories, which can negatively affect patient safety. We implemented a standardized two needle passes for CS and collection of all needle rinses and additional pass material in CytoRich Red for ThinPrep LBP and compared the non-diagnostic and diagnostic rates before and after this intervention. There were 290 pre-intervention cases and 348 post-intervention cases; of which, there were 17 (5.9%) non-diagnostic cases of the pre-intervention group and 27 (7.8) non-diagnostic cases of the post-intervention group. There was no statistically significant difference in non-diagnostic and diagnostic rates before and after the change (p = 0.347 by two-tailed Z test).

Comparison of Liquid-Based Preparations with Conventional Smears in Thyroid Fine-Needle Aspirates: A Systematic Review and Meta-Analysis

BACKGROUND

To compare conventional smears (CSs) and liquid-based preparations (LBPs) for diagnosing thyroid malignant or suspicious lesions.

METHODS

Studies in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane database published up to December 2023. We reviewed 17 studies, including 15,861 samples.

RESULTS

The diagnostic odds ratio (DOR) for CS was 23.6674. The area under the summary receiver operating characteristic curve (AUC) was 0.879, with sensitivity, specificity, negative predictive value, and positive predictive value of 0.8266, 0.8668, 0.8969, and 0.7841, respectively. The rate of inadequate specimens was 0.1280. For LBP, the DOR was 25.3587, with an AUC of 0.865. The sensitivity, specificity, negative predictive value, and positive predictive value were 0.8190, 0.8833, 0.8515, and 0.8562. The rate of inadequate specimens was 0.1729. For CS plus LBP, the AUC was 0.813, with a lower DOR of 9.4557 compared to individual methods. Diagnostic accuracy did not significantly differ among CS, LBP, and CS plus LBP. Subgroup analysis was used to compare ThinPrep and SurePath. The DORs were 29.1494 and 19.7734. SurePath had a significantly higher AUC.

CONCLUSIONS

There was no significant difference in diagnostic accuracy or proportion of inadequate smears between CS and LBP. SurePath demonstrated higher diagnostic accuracy than ThinPrep. Recommendations for fine-needle aspiration cytology should consider cost, feasibility, and accuracy.

Thyroid fine-needle aspiration cytology: malignancy rate in the category of indeterminate significant atypia/indeterminate significant follicular lesion

BACKGROUND

Fine needle aspiration cytology (FNAC) is a standard preoperative diagnostic modality for thyroid nodules. The Bethesda Thyroid Cytopathology Reporting System (TBSRTC) defines the FNAC atypia group as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS).

OBJECTIVES

Determine the risk of malignancy after surgical resection in patients with AUS/FLUS.

DESIGN

Retrospective.

SETTING

Pathology department of a tertiary care center.

PATIENTS AND METHODS

All thyroid FNACs between 2015 and 2023 that were diagnosed as AUS/FLUS in Turkey. Patient demographics, preoperative ultrasonographic features, and follow-up data were collected.

MAIN OUTCOME MEASURES

Relationship between AUS/FLUS diagnosis and final histopathological diagnosis.

SAMPLE SIZE

562.

RESULTS

In total, 562 thyroid nodules were diagnosed as AUS/FLUS, and 267 (47.5%) were surgically excised. A malignant histopathological diagnosis was given in 28 cases (10.4%). Malignancy risk sensitivity of AUS/FLUS diagnosis was 75.68% (95% CI=58.80-88.23%), specificity was 55.24% (95% CI=50.91-59.52%), positive predictive value was 10.49% (95% CI=8.71-12.58%), and negative predictive value was 97.04% (95% CI=94.86-98.31%). In the ultrasonographic data, having symptomatic nodules, nodule calcification, and irregular nodule borders were all statistically significant signs of cancer in a one-variable analysis (P<.01). The presence of a family history emerged as a statistically significant prognostic marker for malignancy (P=.012). Although not statistically significant, the malignancy rate for nodules with nuclear atypia was 11.9%, significantly higher than the rate of 8.3% for nodules with architectural atypia only (P=0.32).

CONCLUSIONS

The diagnosis of AUS/FLUS has a high rate of predicting the risk of malignancy and should continue to be offered. In addition to cytopathological features, ultrasound data and family history should be taken into consideration when evaluating the case.

LIMITATIONS

Retrospective design and no molecular studies.

Evaluation of the diagnostic efficacy of liquid-based cytology obtained via percutaneous ultrasound-guided fine-needle aspiration for pancreatic masses: a large tertiary center's 8-year experience

PURPOSE

There were limited data on the diagnostic efficacy of liquid-based cytology (LBC) for pancreatic tissues acquired by percutaneous ultrasound-guided fine-needle aspiration (US-FNA). This study aimed to evaluate the diagnostic value of LBC acquired via percutaneous US-FNA for pancreatic tumors compared with LBC combined with smear cytology (SC).

METHODS

A retrospective database search (January 2014 and February 2022) was performed for patients who underwent percutaneous US-FNA with both LBC and SC. Clinical and pathological data were collected from 298 patients; eventually, 251 cases met the inclusion criteria. Diagnostic accuracy, sensitivity (SEN), specificity (SPE), positive predictive value (PPV) and negative predictive value (NPV) were compared. Rapid on-site evaluation (ROSE) was not available in all cases.

RESULTS

Based on the pancreaticobiliary cytology guidelines published by the Papanicolaou Society of Cytopathology, 224 (89.2%), 13 (5.2%) and 14 (5.6%) cases were diagnosed as malignant, pre-malignant and benign lesions, respectively. The diagnostic accuracy of the LBC + SC (88.5%) was better than that of LBC (87.3%) but without statistical significance (P = 0.125). The SEN, SPE, PPV and NPV were 87.5%, 85.2%, 98.0% and 45.1%, respectively, in the LBC group and 88.8%, 85.2%, 98.0% and 47.9%, respectively, in the LBC + SC group. According to univariate and multivariate analyses, there were no factors have significant association with the diagnostic sensitivity of LBC.

CONCLUSIONS

LBC obtained via percutaneous US-FNA provides good diagnostic value for pancreatic lesions and there was no significant difference between the diagnostic accuracy of LBC and LBC + SC when ROSE was unavailable.

A Comparative Analysis of Liquid-Based Cytology and Conventional Smears in Fine-Needle Aspirates of Thyroid Lesions

Background Palpable nodules in the thyroid are present in 4-7% of the general population. Fine-needle aspiration cytology is a safe and cost-effective method of choice for evaluating thyroid nodules. Aspirated samples can be manually spread directly onto the slide and stained in the conventional smear method. The liquid-cased cytology method has been recently introduced, which is an automated machine-based method, yielding a single slide with a clean background and greater preservation of cells and consuming less time for screening. This study aimed to compare the cytomorphological features and diagnostic accuracy of conventional smears and liquid-based cytology smears. Methodology This prospective study comprised 250 cases of thyroid lesions. Fine-needle aspiration cytology using conventional smears and liquid-based cytology smears was reported per the Bethesda system of reporting thyroid cytopathology. Detailed cytomorphological features were evaluated and compared in both techniques. Results The cellularity of conventional smears was significantly higher for scores 2+ and 3+ than paired liquid-based cytology smears (paired t-test, p < 0.001). The overall diagnostic efficacy of conventional smears and liquid-based cytology smears was equivalent in the majority of cases (n = 171, 68.4%). Conventional smears were better than liquid-cased cytology smears in 34 (13.6%) cases, and liquid-based cytology smears were better than conventional smears in eight (3.2%) cases. Liquid-based cytology smears showed a higher unsatisfactory rate compared to conventional Smears (15.6% vs. 5.2%). The sensitivity and specificity of conventional smears were 84.6% and 94.4%, respectively, compared to 68.7% and 92.4%, respectively, of liquid-based cytology smears. Conclusions Conventional smears are a cost-effective and easy method for diagnosing thyroid nodules. Liquid-based cytology smears can be used in association with conventional smears to enhance the accuracy of the evaluation of malignant thyroid nodules.

Diagnostic utility of conventional and liquid-based cytology in the management of thyroid lesions; an institutional experience

Objectives:

Liquid-based cytology (LBC) is becoming a useful method in evaluating both gynecological and nongynecological preparations. Many studies have been conducted these days to see the quality of LBC in diagnosing thyroid lesions and its role is yet to be standardized. This study has been done to pick the cytomorphological features of thyroid lesions on LBC and to compare them with the conventional cytology of these lesions.The objective of the study is to evaluate the efficacy of thyroid fine-needle aspiration cytology processed by LBC as compared to conventional smears.

Material and Methods:

A prospective study has been done on 53 cases of thyroid lesions using standard conventional and LBC techniques.

Results:

In most of the cases, the cytological features are similar in conventional cytology smears and LBC, but the colloid film and the lymphocytic component show a clear picture on direct smears, whereas nuclear and cytoplasmic details are better evaluated in LBC slides. The preservative solution used in LBC could be efficiently used for the application of immunocytochemical and molecular techniques.

Conclusion:

LBC does not represent as a valid alternative to conventional cytology but it can be considered as a diagnostic utility process especially due to the possibility of applying additional techniques which enhance the efficacy of the cytological diagnosis of thyroid lesions.

Should Liquid Based Cytology (LBC) be Applied to Thyroid Fine Needle Aspiration Cytology Samples?: Comparative Analysis of Conventional and LBC Smears

Context:

Liquid-based cytology (LBC) is a cyto-preparatory technique that may be applied to fine-needle aspiration (FNA) samples. However, its efficacy over conventional smears (CS) in thyroid is controversial.

Aims:

The aim of this study was to compare CS versus LBC (SurePath, BD) preparations in thyroid FNA samples for diagnostic efficacy.

Settings and Design:

Prospective case-control study using split sample analysis in 200 non-consecutive cases of thyroid FNA reported as per the Bethesda system.

Methods and Material:

Detailed cytomorphological features were evaluated in CS and LBC preparations. Cellularity was scored as 0–3. Based on diagnostic efficacy, they were categorized into three groups:(i) CS and LBC equivalent for diagnosis, (ii) CS better than LBC, and (iii) LBC better than CS for providing the diagnosis.

Statistical Analysis Used:

Paired t test for cellularity scores and descriptive for diagnostic efficacy.

Results:

There were 7 unsatisfactory, 118 benign, 10 atypia or follicular lesion of undetermined significance, 25 follicular neoplasms, 6 suspicious for malignancy, and 34 malignant thyroid FNA cases based on routine conventional smears. Cellularity of conventional smears was significantly higher than paired LBC smears (paired t test, P < 0.005). Comparison of overall diagnostic efficacy showed that LBC and CS were equivalent in 59% of cases; CS was superior to LBC in 37% cases and LBC was better than CS in 4% cases only. LBC smears showed higher unsatisfactory rate as compared to CS (18% vs. 3.5%). In category 2, the two techniques were equivalent in 87% of cases. In categories 4 and 6, CS were superior to LBC.

Conclusions:

In thyroid FNA cases, conventional smears are superior to LBC preparation in terms of cellularity and diagnostic efficacy and hence, LBC preparations should not replace conventional smears for making a routine cytomorphological diagnosis.

Comparison of Diagnostic Rates and Concordance with Subsequent Surgical Resections between Conventional Smear and ThinPrep Preparations versus ThinPrep Only in Thyroid Fine Needle Aspiration (T-FNA) Specimens

BACKGROUND

Thyroid fine needle aspiration (T-FNA) is a mainstay in management of thyroid nodules. However, the preparation of T-FNA specimens varies across institutions. Prior studies have compared diagnostic rates between different specimen preparations of T-FNA specimens and their associated advantages and disadvantages. However, few have compared the rates of all diagnostic categories of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) between liquid-based preparations (LBPs) and a combination of LBP and conventional smear (CS) preparations. Our study compares TBSRTC diagnostic rates between these 2 cohorts and correlates cytologic diagnoses with subsequent thyroid resections to evaluate rates of neoplasia (RON) and malignancy (ROM).

METHODS

584 consecutive thyroid FNA specimens were collected and stratified by preparation type (ThinPrep [TP] vs. CS &amp; TP). Diagnostic rates for each TBSRTC diagnostic category were calculated. The institution's electronic medical records database was searched for histologic diagnoses of previously sampled thyroid nodules to evaluate the RON and ROM.

RESULTS

Of 584 thyroid FNA specimens, 73 (12.5%) and 511 (87.5%) were evaluated by TP only and CS &amp; TP, respectively, reflecting the predominance of rapid on-site evaluation (ROSE) with CS for T-FNAs at our institution. Of the TP only and CS &amp; TP cohorts, 29 (39.7%) and 98 (19.2%) had subsequent resections, respectively. The frequency of non-diagnostic cases was lower in the CS &amp; TP cohort (12.7% vs. 26%). While the diagnostic rate of follicular lesion of undetermined significance was similar for both cohorts, SFN categorization was only utilized in the CS &amp; TP cohort (1.5% vs. 0%). Although RON and ROM were similar between cohorts in many of the TBSRTC categories, there was a higher RON associated with non-diagnostic specimens in the TP only cohort when the denominator included all non-diagnostic cases.

CONCLUSION

The combination of CS and LBP may potentially decrease the non-diagnostic rate of T-FNA specimens as well as the number of passes required for diagnosis, particularly with ROSE. Evaluation of morphologic features highlighted in conventional smears may facilitate diagnostic categorization in the "suspicious for follicular neoplasm" category.

Comparison of smear cytology with liquid-based cytology in pancreatic lesions: A systematic review and meta-analysis

BACKGROUND

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) is a safe and accurate technique to confirm the diagnosis of pancreatic cancers. Recently, numerous studies comparing the diagnostic efficacy of smear cytology (SC) and liquid-based cytology (LBC) for pancreatic lesions yielded mixed results.

AIM

To compare and identify the better cytology method for EUS-FNA in pancreatic lesions.

METHODS

A comprehensive search of PubMed, Embase, and Cochrane was undertaken through July 18, 2020. The primary endpoint was diagnostic accuracy (sensitivity and specificity). Secondary outcomes included sample adequacy and post procedure complications. In addition, factors affecting diagnostic efficacy were discussed.

RESULTS

Data on a total of 1121 comparisons from 10 studies met the inclusion criteria. Pooled rates of sensitivity for SC and LBC were 78% (67%-87%) vs 75% (67%-81%), respectively. In any case, both SC and LBC exhibited a high specificity close to 100%. Inadequate samples more often appeared in LBC compared with SC. However, the LBC samples exhibited a better visual field than SC. Very few post procedure complications were observed.

CONCLUSION

Our data suggested that for EUS-FNA in pancreatic lesions (particularly solid lesions), SC with Rapid On-Site Evaluation represents a superior diagnostic technique. If Rapid On-Site Evaluation is unavailable, LBC may replace smears. The diagnostic accuracy of LBC depends on different LBC techniques.

Evaluation of Thyroid Fine-Needle Aspiration Biopsies according to Cytological Methods and Comparison with Histopathological Diagnosis

Objectives:

In this study, we aim to compare the results of aspiration of thyroid nodules evaluated according to the Bethesda category (BC) with tissue diagnoses in the operation materials and to compare the sensitivity, specificity and accuracy rates according to cytology methods.

Methods:

The previous fine-needle aspiration biopsy (FNAB) of thyroid nodules of 879 cases diagnosed histopathologically between 2010 and 2017 was examined. The FNAB results determined according to the Bethesda system were matched with tissue diagnoses, sensitivity, specificity, and accuracy rates were investigated according to cytology methods.

Results:

Sensitivity, specificity, Positive predictive value (PPV), Negative predictive value (NPV) and accuracy rates were found in all FNAB results (in units of %; Sensitivity; 84.7, Specificity; 81.1, PPV; 74.1, NPV; 89.2, Accuracy; 82.5). All of the cytological evaluation methods of thyroid FNABs were found to be reliable and effective (Generally, the results are 80% and above). Specificity and accuracy rates were close to the general average (82.5%) in all methods. However, in cases evaluated with liquid base cytology (LBC) method and in addition to LBC or conventional smear (CS), the sensitivity rates in cases where cell block (CB) were evaluated together were higher than cases in which LBC and CS were used alone (92.6% and 91.0%). When examined statistically, there was no significant difference concerning sensitivity, specificity and accuracy rates of cytological methods (p>0.05, respectively, p=0.576, 0.065, 0.643).

Conclusion:

In cytopathology, when evaluating thyroid aspirations, it is seen that the LBC method is used instead of CS. In our study, we recommend the use of the LBC method, which seems to have the highest sensitivity (taking into account its technical advantages), instead of CS. However, we think that both CS and LBC methods should be evaluated by supporting them with cell block sections.

2020 Chinese guidelines for ultrasound malignancy risk stratification of thyroid nodules: the C-TIRADS

Thyroid nodules are very common all over the world, and China is no exception. Ultrasound plays an important role in determining the risk stratification of thyroid nodules, which is critical for clinical management of thyroid nodules. For the past few years, many versions of TIRADS (Thyroid Imaging Reporting and Data System) have been put forward by several institutions with the aim to identify whether nodules require fine-needle biopsy or ultrasound follow-up. However, no version of TIRADS has been widely adopted worldwide till date. In China, as many as ten versions of TIRADS have been used in different hospitals nationwide, causing a lot of confusion. With the support of the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association, the Chinese-TIRADS that is in line with China's national conditions and medical status was established based on literature review, expert consensus, and multicenter data provided by the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound.

Comparison of smear cytology and liquid-based cytology in EUS-guided FNA of pancreatic lesions: experience from a large tertiary center

BACKGROUND AND AIMS

Studies comparing the diagnostic efficacy of liquid-based cytology (LBC) and smear cytology (SC) of pancreatic tissue sampling obtained via EUS-guided FNA (EUS-FNA) are still insufficient, mainly because results were controversial. We compared the diagnostic efficiency of LBC and SC of EUS-FNA of pancreatic lesions in one of the largest tertiary hospitals in China.

METHODS

A retrospective database search (January 2015 to January 2019) was performed for patients who underwent EUS-FNA with both LBC and SC. Demographic, cytologic, and endosonographic data were collected from 819 patients; 514 cases met the inclusion criteria. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were compared. Rapid on-site evaluation was not available in all cases.

RESULTS

Three hundred eighty-five cases (74.90%) had confirmed malignancy, and 40 cases (7.78%) confirmed benign neoplasm. Adequate tissue sampling rates showed no significant difference between the 2 groups. The sensitivity, accuracy, and negative predictive value (NPV) of LBC were higher than those of SC with statistical significance (71.4% vs 55.1%, 76.1% vs 61.6%, and 40.6% vs 27.7%, respectively). The sensitivity, accuracy, and NPV of combined SC and LBC were higher than those of LBC alone with statistical significance (83.9% vs 71.4%, 86.5% vs 76.1%, and 56.8% vs 40.6%, respectively). Multivariate analysis revealed that pancreatic neck/body/tail lesions (P = .003), solid lesions (P < .001), 22-gauge needle size (P < .001), and number of needle passage >3 (P = .041) were associated with higher diagnostic sensitivity in all participants using LBC, whereas number of needle passage >3 (P = .017) was associated with higher diagnostic sensitivity using SC.

CONCLUSIONS

LBC was more accurate and sensitive than SC in EUS-FNA of pancreatic lesions with higher NPV when rapid on-site evaluation is unavailable. Pancreatic neck/body/tail lesions, solid lesions, 22-gauge needle, and more than 3 passes were associated with higher sensitivity when using LBC. Performing more than 3 passes is associated with higher sensitivity when using SC.

A comparative study of two liquid-based preparation methods: membrane-based and sedimentation in fine needle aspiration cytology diagnosis in thyroid nodules

Background

As thyroid fine needle aspiration (FNA) shows a certain limitation in the diagnosis of conventional smears, novel approaches like liquid-based cytology (LBC) have been gradually applied recently. Studies have shown the difference between the conventional smears (CSs) and liquid-based smears on fine needle aspiration cytology (FNAC) diagnosis, but the impacts of different liquid-based preparation (LBP) methods, including membrane-based and sedimentation, on diagnosis are still not clear. In this study, the effects of liquid-based smears prepared by different methods on the cytological interpretation were studied.

Methods

A total of 221 thyroid liquid-based FNAC cases from January 2017 to October 2018 were collected. We retrospectively studied and compared the effects of the membrane-based and sedimentation LBP methods through The Bethesda System for Reporting Thyroid Cytopathology (TBS) diagnosis and risk of malignancy assessment. Besides, we made an evaluation on the diagnostic differences in the effects of different preparation methods on the cell morphology and tissue structure of papillary thyroid carcinoma (PTC) for more accurate FNAC diagnosis.

Results

Among the 221 cases reviewed, membrane-based method was applied in 153 cases and sedimentation in 68 cases. According to the diagnostic criteria of 2017 TBS, TBSVI and TBSV thyroid could be cytologically diagnosed by membrane-based (49.0% (75/153) and 25.5% (39/153)) and sedimentation (52.9(36/68) and 25(17/68)) methods, and both were confirmed as PTC through histopathological diagnosis after operation, with the malignancy degree as high as 100%. In addition, of the 30 cases that were diagnosed as TBSIII thyroid nodules with the membrane-based method, 15 cases were pathologically malignant after an operation, with the malignancy degree of 50% (15/30), while that in 11 cases using the sedimentation method was 45.4% (5/11). PTC could be detected in both the TBSIV and TBSII thyroid nodules diagnosed by membrane-based method, with the sensitivity of 87.0% (114/131) lower than that by sedimentation method (91.4% (53/58)), showing the lower consistency with the histopathological result (K = 0.635 vs K = 0.757). Among the membrane-based smears, 23.5% (36/153) had fewer follicular epithelial cells, 55.6% (20/36) of which were considered to be suspicious for PTC from cell karyotype and tissue arrangement. While among the sedimentation smears, 16.2% (11/68) had fewer follicular epithelial cells, and 63.6% (7/11) was suspicious for PTC. In 72.5% (95/131) membrane-based smears of PTC, the papillary and swirling structures were not obvious, showing as crowded syncytial cell masses, while in 55.2% (32/58) sedimentation smears, both structures were visible with obvious three-dimensional papillary structure, and the fibrovascular axis still remained.

Conclusion

LBP technique is feasible for FNAC diagnosis, and the sedimentation shows more advantages, like higher PTC detection rate and good consistency with postoperative histopathological diagnosis. A clear understanding of the subtle differences in the effects of membrane-based and sedimentation methods on the cell morphology and tissue structure could be conducive to the definitive diagnosis of PTC before operation.

Variants of Papillary Thyroid Carcinoma: An Algorithmic Cytomorphology-Based Approach to Cytology Specimens

BACKGROUND

Thyroid cancer accounts for 1% of cancer cases in developed countries, in which papillary thyroid carcinoma (PTC) is the most common type. There are multiple variants of PTC described to date, some of them with aggressive behavior and poor clinical outcome. These variants are well described and accepted in recent guidelines of many international societies, and the prognostic and management implications are well laid out. Due to their established clinical importance and to guide appropriate surgical management, it is now imperative in clinical practice, including cytopathology, to differentiate aggressive variants from nonaggressive ones. This review aims to describe the variants of PTC and to provide a practical algorithmic approach to facilitate the cytological diagnosis of these variants.

SUMMARY

Subtyping PTC variants on fine needle aspiration cytology (FNAC) is challenging even for the most experienced cytopathologist. To facilitate a correct subtyping on FNAC, we propose a stepwise approach that is mainly designed for conventional smear methodology. This approach requires first to stratify the lesions into oncocytic and nononcocytic features before analyzing further details in cell morphology and pattern. Key Messages: (1) Subtyping in PTC is possible on cytopathology. (2) The main aim of the cytopathologist is to differentiate aggressive from nonaggressive variants. (3) The subtyping of PTC can help in the surgical management of the patients.

Comparison of cytological adequacy and pain scale score in ultrasound-guided fine-needle aspiration of solid thyroid nodules for liquid-based cytology with with 23- and 25-gauge needles: a single-center prospective study

In ultrasound (US)-guided fine-needle aspiration (FNA) of solid thyroid nodules (STN) using liquid-based cytology (LBC), the most appropriate needle size for LBC remains unclear. This study compared the cytological adequacy and complications associated with using 23- and 25-gauge needles in US-guided FNA of STNs using LBC. US-guided FNA was performed in consecutive patients by one radiologist to diagnose STNs ≥ 5 mm in the largest diameter. The one-sampling technique through a single needle puncture and multiple to-and-fro needle motions was used in each patient. The 23- and 25-guage needles were used consecutively each day. After FNA, the pain and complications experienced by each patient were investigated by a nurse, who was blinded to the information of needle gauge used. A cytopathologist retrospectively analyzed the cytological adequacy and cellularity of the cases. Of the 99 STNs, eight (8.1%) exhibited inadequate cytology (4 each with 23- and 25-gauge needles). The rate of cytological adequacy was not statistically different between the groups (p = 0.631). The mean pain scale values with 23- and 25-gauge needles were 2.1 ± 1.3 and 1.6 ± 1.3, respectively (p = 0.135). There were no significant complications in either group. In conclusion, both 23- and 25-gauge needles are useful in LBC because cytological adequacy and complications were not statistically different with both sizes of the needles.

Can liquid-based preparation substitute for conventional smear in thyroid fine-needle aspiration? A systematic review based on meta-analysis

OBJECTIVE

Conventional smear (CS) using fine-needle aspiration cytology (FNAC) has been established as the test of choice for diagnosing thyroid lesions, despite low sample adequacy and inter-individual variations. Although a liquid-based preparation (LBP) technique has been recently applied to overcome these limitations, its clinical utility and its accuracy over CS are controversial. This study aimed to determine the true sensitivity and specificity of LBP in thyroid FNAC by meta-analysis.

DESIGN

Systematic review with meta-analysis.

METHODS

We searched major electronic databases (MEDLINE, EMBASE, Cochrane library, Google Scholar) with queries of 'thyroid', 'LBP' and 'liquid-based cytology'. Original articles including cytohistologic correlation data comparing the accuracy of any LBP technique, such as ThinPrep, SurePath and Liqui-Prep, with CS were included for qualitative meta-analysis and preparation of synthesized reporter-operating curves (sROC).

RESULTS

A total of 372 studies were screened and 51 original articles were eligible for full-text review; finally, 24 studies were chosen for the meta-analysis. Average sample inadequacy was significantly lower in two mainstream LBP methods (ThinPrep and SurePath) than CS. Specificity and sensitivity by sROC were similar or slightly superior for LBP vs CS. Various cytomorphologic changes by each method have been reported.

CONCLUSIONS

Although a learning curve is essential for adapting to the cytomorphologic features of the LBP technique, our results support the use of two mainstream LBPs alone in thyroid FNAC that LBP will increase the sample adequacy and reduce the workload with similar accuracy. More data and further evaluation are needed for the other LBP methods.

Comparison of conventional cytology and SurePath in split thyroid fine needle aspiration materials

OBJECTIVE

The aim of the present study was to compare the cytomorphological features and cytopathological diagnoses in thyroid aspiration materials prepared by SurePath® (SP) and conventional cytology (CC).

MATERIALS AND METHODS

Fine needle aspiration (FNA) materials from 180 thyroid nodules were divided into two groups to prepare three conventional smears and one SP slide. Twenty-nine cytomorphological features of thyroid lesions were compared in the CC and SP slides. The Kappa coefficiency was determined for each. The cytopathological diagnosis of CC and SP were compared.

RESULTS

The feature with the lowest Kappa coefficient was the haemorrhagic background, whereas nuclear molding had the highest Kappa coefficient. The rates of the atypical and suspicious cytopathological diagnostic categories were decreased, whereas the rates of benign and malignant categories were increased in SP. When the cytopathological diagnoses of CC and SP were compared with the histopathological diagnoses of the 31 thyroidectomy materials, the results were similar.

CONCLUSION

The common problems seen in CC, such as an excessive number of slides, a haemorrhagic background and air drying artefact in the SP method were not encountered. Through these advantages, the rate of the indeterminate cytopathological diagnosis was low in SP. In addition to those advantages, the increased rates of non-diagnostic cases, the difficulty in evaluating the cytomorphologic features owing to tridimensional structures and the smaller size of the cells and the presence of tridimensional structures uninterpreted microscopically were the disadvantages of SP. The present results showed that SP could be used instead of CC in thyroid cytopathology.

Combined use of conventional smear and liquid-based preparation versus conventional smear for thyroid fine-needle aspiration

The purpose of the study was to compare the diagnostic utility of the combined conventional smear (CS) and liquid-based preparation (LBP) compared to CS with respect to the non-diagnostic rate, the atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) rate, and the diagnostic performances for malignancy. This retrospective study was approved by the Institutional Review Board, and the need to obtain informed consent was waived. In our institution, thyroid FNAs were processed with CS before October 2012, and LBP has been used in combination with CS after October 2012. On-site evaluation for the adequacy of CS was not performed. This study included nodules 5 mm or larger with FNAs performed by faculties: 811 nodules in 773 patients for CS, and 926 nodules in 894 patients for combined CS and LBP. Nodules with surgery or either benign or malignancy cytology on initial or repeat FNA were regarded to have the reference standards needed to calculate diagnostic performances. The proportion of Bethesda categories and diagnostic performances were compared between the two groups with z test. The non-diagnostic rate, the AUS or FLUS rate, and the diagnostic performances for malignancy were similar (All P > 0.05). The follicular neoplasm (FN) or suspicious for FN rate decreased from 1.2 to 0.3 % (P = 0.034). The benign rate increased from 51.4 to 57.0 % (P = 0.019). Combined CS and LBP decreased FN or suspicious for FN diagnoses, and increased benign diagnoses compared to CS with comparable non-diagnostic rates and AUS or FLUS rates, and comparable diagnostic performances.

Cytotechnologist Performance for Screening Hürthle Cell Atypia in Indeterminate Thyroid Fine-Needle Aspirates

OBJECTIVES

We have previously shown that specimens diagnosed as containing Hürthle cells have a 12% chance of being malignant if they are classified as atypia of undetermined significance (AUS-HC). The identification of Hürthle cells by cytotechnologists (CTs) during screening can improve cytopathologist efficiency and may prevent diagnostic errors due to the oversights of focal findings. Here, we examine the performance of our institutional CTs when screening for Hürthle cell atypia in thyroid fine-needle aspiration (FNA) specimens.

STUDY DESIGN

Information on 8,814 thyroid cytopathology specimens was retrieved for a 10-year period. Specimens were screened by 1 of 11 CTs. A subsample of cases was categorized either as AUS-HC or suspicious for Hürthle cell neoplasm.

RESULTS

AUS-HC screening diagnoses were more likely to be downgraded to benign but less likely to be upgraded compared to AUS diagnoses with nuclear or microfollicular atypia. AUS-HC represents almost all papillary thyroid carcinoma (PTC) screening diagnoses downgraded to the AUS category, which suggests that even low levels of Hürthle cell atypia can result in PTC being included in the differential diagnosis.

CONCLUSION

Overall, there are few major discrepancies between CT and pathologist diagnoses for specimens containing Hürthle cell atypia.