Utility of thin-layer preparations in thyroid fine-needle aspiration: diagnostic accuracy, cytomorphology, and optimal sample preparation

Cytomorphological comparison of ThinPrep and SurePath liquid-based cytology in thyroid fine-needle aspiration

BACKGROUND

The two widely established systems for liquid-based cytology (LBC), ThinPrep and SurePath, employ different principles. The aim of this study was to compare the cytomorphology of thyroid lesions prepared by the two techniques.

METHODS

We retrospectively reviewed 44 thyroid FNA specimens prepared by LBC, including 20 ThinPrep and 22 SurePath. Cytologic diagnoses were made according to the Bethesda system and cytomorphologic parameters were evaluated.

RESULTS

Acellular smears were significantly frequent in ThinPrep than SurePath (10% vs. 0%). Both techniques produced a clean background, well cell preservation, and not apparent cell shrinkage. ThinPrep showed significantly lower cellularity than SurePath (25% vs. 4.3%). ThinPrep produced considerable flattening and fragmented clusters, while SurePath contained larger clusters in a three-dimensional configuration. Colloid was significantly reduced in amount and fragmented in ThinPrep, and was easily observed in SurePath. In cases of Hashimoto's thyroiditis, ThinPrep produced much less leukocytes in background than SurePath. Aggregates of fibrin and leukocytes were frequently present in 10/16 cases (62.5%) processed by ThinPrep. Air-dry artifact at periphery of the ring was present in 6/16 cases (37.5%) processed by ThinPrep. The nuclear features of papillary carcinoma were similarly evident in both LBC preparations.

CONCLUSION

SurePath seems to be superior to ThinPrep for diagnosing benign entities based on adequate representation of colloid and lymphocytes. The cell quality of both techniques in thyroid FNA was comparable, while each method introduces its own unique cytologic artifacts related to its methodology. We should recognize the cytomorphologic alterations to avoid misinterpretations.

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.

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.

Utility of cell block as an adjunct to liquid-based cytology for diagnosing papillary thyroid carcinoma

Background

Although liquid-based cytology (LBC) has gained popularity among clinical laboratories, it is unclear whether it is equivalent to conventional smears for making a definite diagnosis of papillary thyroid carcinoma (PTC). The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) suggests a definite diagnosis of PTC is preferred when there are at least one of three features (papillary architecture, psammomatous calcifications, and frequent pseudonuclear inclusions) plus other typical cytomorphological findings. This study evaluated whether an additional cell block (CB), prepared from the residual LBC material, could help improve the diagnosis of PTC.

Materials and Methods

A total of 62 cases with both ThinPrep LBC and CB preparations and histopathological follow-up of PTC were retrieved between November 2016 and March 2019. The ThinPrep LBC and CB slides were reviewed separately to identify any papillary architecture, psammomatous calcifications, or pseudonuclear inclusions for diagnosing PTC.

Results

Among the 51 cases with cytological diagnosis of PTC in the LBC+CB slides, the CB provided additional diagnostic information in 15 cases, which were initially diagnosed as suspicious for PTC based on the LBC slides alone. This information included papillary architecture (n=11), psammomatous calcification (n=1) and pseudonuclear inclusions (n=5). The number of specimens in the 51 cases containing at least one of the three features increased from 42 (LBC) to 51 (LBC+CB). The accuracy for diagnosing PTC increased from 58.1% for LBC alone to 82.3% for the LBC+CB examination.

Conclusion

An adjunctive CB preparation may improve the LBC technique for diagnosing PTC.

A Large Thyroid Fine Needle Aspiration Biopsy Cohort with Long-Term Population-Based Follow-Up

Background: Prior studies evaluating thyroid fine needle aspiration biopsies (FNABs) have limited the calculation of risk of malignancy (ROM) to cytologic specimens with corresponding histologic specimens, and clinical follow-up for those patients who do not undergo immediate surgery has been largely disregarded. Moreover, there is marked variability in how researchers have approached thyroid FNAB statistical analyses. This study addresses the urgent need for information from a large cohort of patients with long-term clinical follow-up to more accurately determine the performance of thyroid FNAB and ROM for each diagnostic category. Methods: A retrospective review of the University of California, San Francisco (UCSF), pathology database for thyroid FNABs from January 1, 1997, to December 31, 2004, was performed. Diagnoses were coded using the 2017 The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), and patients were matched to both the UCSF cancer registry and California Cancer Registry. Data were analyzed using the Kaplan-Meier method, and stratified by TBSRTC diagnostic category. Kaplan-Meier curves were used to estimate incidence rates of malignancy, stratified by FNAB category. Cox proportional hazards models were used to determine the instantaneous ROM. Results: Initial FNABs from 2207 patients were included. Median follow-up period after the first thyroid FNAB was 13.9 years (range: 10.5-18.4 years). During follow-up, there were 279 confirmed diagnoses of thyroid malignancy. Estimates derived from Kaplan-Meier curves demonstrated that the risk of having a thyroid malignancy was low for nondiagnostic and benign categories, intermediate for atypia of undetermined significance (AUS), follicular lesion of undetermined significance (FLUS), AUS/FLUS combined, and follicular neoplasm, and high for suspicious and malignant categories. A total of 52/1575 false-negative cases (3.2%) were identified. Excluding papillary microcarcinomas, the false-negative rate was 1.5% (23/1575). No patients with a false-negative diagnosis died of thyroid cancer during the follow-up period. Conclusions: Asymptomatic patients with low-risk clinical and radiologic features and initially benign or unsatisfactory biopsy are unlikely to develop thyroid malignancy and highly unlikely to die of thyroid cancer. FNAB is highly accurate in detecting malignancy. Additional studies evaluating similar large data sets after the adoption of TBSRTC and the integration of molecular testing are needed.

Clinical Application of Ultrasound-Guided Thyroid Fine Needle Aspiration Biopsy and Thinprep Cytology Test in Diagnosis of Thyroid Disease

Purpose:

To study the clinical application value of ultrasound guided thyroid fine needle aspiration biopsy and thinprep cytology testing in diagnosis of thyroid disease.

Methods:

A total of 78 patients with thyroid nodules were enrolled, 34 males and 44 females, aged 33-64 years old with mean age of 47.6 years. All underwent thyroid module fine needle puncture after surgery to assess cell pathology and histopathological features.

Results:

Sufficient specimens were obtained from all of 78 patients, the cytological results of 73 cases (93.6 %) being consistent with pathological results. While 20 cases (25.6 %) were malignant tumors, 44 (56.4 %) were benign and 9 (11.5 %) were non-tumor lesions. The sensitivity of benign and malignant thyroid nodule by thyroid fine needle puncture was 90.9 %, specificity was 98.1 % and the positive predictive value was 96.3 %.

Conclusions:

It is demonstrated that ultrasound-guided thyroid fine needle aspiration biopsy and thinprep cytology testing have diagnostic value in clinical application for thyroid disease, showing good diagnostic coincidence rates with histopathological examination. They can thus be regarded as safe and effective for preoperative diagnosis and providing an appropriate basis for selection of surgery.

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.

A Comparison of the Results of Monolayer versus Smear Cytopreparatory Techniques for Fine-Needle Aspiration in 100 Consecutive Patients Undergoing Thyroidectomy: A Surgeon's Perspective

OBJECTIVE: To compare thyroid fine-needle aspiration (FNA) using monolayer (MT) versus conventional smear (CS) cytopreparatory techniques with final histology.

STUDY DESIGN: Retrospective review of 100 consecutive thyroidectomies.

SETTING: Tertiary care university affiliated medical center.

RESULTS: 26% of MT aspirates were inadequate compared with 3% of CS aspirates ( P < 0.05). The negative predictive values for MT and CS were 86% and 100%, respectively. The positive predictive values for MT and CS were 69% and 90%, respectively.

CONCLUSIONS: Fewer inadequate specimens will be obtained with CS than with MT. A clinician performing FNA can obtain adequate specimens at a rate comparable to that of a hospital-based cytopathologist.

SIGNIFICANCE: CS provides greater assurance to the patient and the surgeon that a thyroid nodule with a FNA interpreted as benign can be observed. A higher percentage of patients with malignant tumor will receive thyroidectomy with the use of CS technique for FNA. EBM rating: B-3. (Otolaryngol Head Neck Surg 2004;131:964–7.)

Conventional smears versus liquid-based preparations for thyroid fine-needle aspirates: a systematic review and meta-analysis

INTRODUCTION

Thyroid fine-needle aspiration has traditionally been prepared using conventional smears (CS). Liquid-based preparations (LBP) have grown in popularity and yet, there is a lack of consensus about which method is superior. This review compared CS and LBP as an intervention in the management of thyroid nodules.

MATERIALS AND METHODS

Medline, EMBASE, Scopus and ClinicalTrials.gov were searched to locate relevant studies. Observational studies comparing CS and LBP of consecutive thyroid fine-needle aspirations were included. Two reviewers independently screened, extracted, and entered data. Double data extraction included the following outcomes: (1) the proportion of inadequate smears and (2) the proportion of indeterminate smears. Studies were also assessed for risk of bias and heterogeneity.

RESULTS

From 599 unique studies, title/abstract screening identified 136 studies, and full text screening identified 13 studies. The 13 studies included 24,307 fine-needle aspirations from 19,433 patients and had high clinical, methodological, and statistical heterogeneity with low risk of bias. For CS and LBP, a meta-analysis of 12 studies showed no difference in the proportion of inadequate smears (risk difference: -0.00; 95% confidence interval [CI]: -0.04-0.04); 13 studies showed no difference in the proportion of indeterminate smears (risk difference: -0.02; 95% CI: -0.05-0.01). Sensitivity analysis of studies with low risk of bias had similar results.

CONCLUSIONS

There is no difference between CS and LBP in the proportion of inadequate and indeterminate smears. Recommendations of one method over the other should be based on cost, feasibility, and accuracy, all of which require further study.

Diagnostic Accuracy of Cerebrospinal Fluid (CSF) Cytology in Metastatic Tumors: An Analysis of Consecutive CSF Samples

BACKGROUND

Cerebrospinal fluid (CSF) examination can be used to verify the presence of primary malignancies as well as cases of central nervous system (CNS) metastasis. Because of its importance, there have been several studies concerning the sensitivity of CSF cytology. To determine the practical use and reproducibility of diagnoses based on CSF cytology, we evaluated this test by analyzing cytology results from consecutive CSF samples.

METHODS

Between July 2010 and June 2013, 385 CSF cytology samples from 42 patients were collected. The samples were gathered using a ventricular catheter and reservoir. CSF cytology of all patients was examined more than two times with immunocytochemistry for cytokeratin.

RESULTS

Primary neoplastic sites and histologic types of patients' metastatic cancer were diverse. The overall sensitivity for detecting malignancy was 41.3%. Even within short-term intervals, diagnoses frequently changed.

CONCLUSIONS

Our results were inconsistent, with low sensitivity, when compared to the results of previous studies. However, CSF evaluation can still provide valuable diagnostic and prognostic information because adjuvant treatments are now routinely performed in patients with CNS metastasis. Negative CSF cytology results should not be ignored, and continuous CSF follow-up is essential for following the clinical course of patients with metastatic cancer involving the CNS.

Morphological and immunocytochemical diagnosis of thyroiditis: Comparison between conventional and liquid-based cytology

The efficacy of thyroid (FNAB) processed by liquid-based cytology (LBC) in Hashimoto's Thyroiditis (HT) in two reference periods, is evaluated. The morphologic features of 820 cases with both methods and the cyto-histological comparison are analyzed. The diagnosis of hyperplastic nodules (HN) in HT, its mimickers especially in presence of oxyphilic cells and the role of immunocytochemistry (IHC) are studied. 150 cases of HT processed by conventional smear (CS) in 1996-98 and 670 with LBC in 2005-2007,were included. The majority of FNAB were carried out under USguidance and fixed with ethyl alcohol for the CS. LBC material was rinsed in the Cytolit solution, processed according to the manufacturer's recommendations. Among the 150 CS, 83 were HT while 67 were HN in HT; in the second triennium 245 LBC were HT and 425 were HN in HT. In the first period a follow-up (including a second FNA or surgery) was done in 92 cases, in the second period in 116. In the surgical group 97.1% in the first period were benign (all HT and 34/36 HN) and 2.8% malignant(all HN). In 2005-2007, 94% were benign (15 HT and 45/49 HN) and 6%malignant. Thirty HN from the second triennium had ICC for HBME-1 and Galectin-3 resulting negative in 93.5%. Among these cases, 10 had a benign histology and a concordant negative ICC. LBC can be used as a valid method for HT, especially for the possible application of ICC to HN, and it allows a correct preoperative selection of lesions

Follicular thyroid neoplasms can be classified as low- and high-risk according to HBME-1 and Galectin-3 expression on liquid-based fine-needle cytology

DESIGN

Fine-needle aspiration biopsy (FNAB) is the most reliable diagnostic tool in the diagnosis of thyroid nodules. A cytologic diagnosis of follicular neoplasm with atypical cells of undetermined significance (FN/AUS) implies that the selection of patients between surgery and follow-up is difficult. In this setting immunocytochemical stainings might be helpful. The efficacy of a panel made up of HBME-1 and Galectin-3 antibodies is evaluated in cases processed by liquid-based cytology (LBC).

METHODS

Out of 7091 thyroid FNAB processed by LBC method, 120 cases undergoing surgery successively were selected. These cases were classified as benign lesion (BL, eight cases), FN, including the ACUS category of the Bethesda classification (FN/AUS, 50 cases), suspicious for malignancy (SM, 59 cases), and malignant neoplasm (MN, three cases). Immunostains for HBME-1 and Galectin-3 were carried out on the LBC slides.

RESULTS

All MN and BL were histologically confirmed. FN/AUS and SM showed a malignancy risk of 24 and 72.9% respectively. The complete immunocytochemical panel was positive in 83.3% of the cases resulting in malignancy and negative in 87.5% of cases resulting in benign histology. Among the FN/AUS, the complete positive immunocytochemical panel was detected in 76.9% of cases resulting as malignant and the complete negative immunocytochemical panel was observed in 96.8% of cases resulting as benign at histology.

CONCLUSIONS

The expression of HBME-1 and Galectin-3 in cases classified as FN/AUS on LBC-processed FNABs can effectively distinguish lesions, which need immediate surgery (high risk or FNH or Thy 3h) from those which can be followed-up (low risk or FNL or Thy 3l).

Follicular nodules (THY3) of the thyroid: we recommend surgery

OBJECTIVE

To determine the need of total thyrodectomy for patients with follicular nodules of thyroid.

SUBJECTS AND METHODS

From January 2005 through June 2008, 2249 consecutive patients (438 males, 1811 females; mean age 54 yr, range 9-87) with thyroid nodules were submitted to 2518 ultrasound-guided fine-needle aspiration (USgFNA) for cytological examination. USgFNA were performed by experienced surgeon (RP) and endocrinologist (RGG) under ultra- sonographyc guidance, using a 10-MHz linear transducer. Liquid-based cytology was used.

RESULTS

All cytological samples were classified in 5 diagnostic classes (THY1, THY2, THY3, THY4, THY5) in agreement with the British Thyroid Association (BTA); 1.4% specimen were classified as THY5, 2.1% as THY4, 7.6% as THY3, 79.5% as THY2 and 9.4% as THY1. In 97% of THY5 patients, malignancy was found. Among THY4 patients, 95.5% were positive for thyroid tumor. Among THY3 patients, malignancy was found in 29.1%. THY3 patients with thyroid tumors were younger than those with benign lesions (46 ± 14.1 yr vs 50 ± 13.8 yr; p<0.05, t test). No statistical difference was found neither in malignancy frequency among men and women nor in mean size of nodules (24 ± 11.8 mm malignant vs 23 ± 9.4 mm benign).

CONCLUSIONS

this study provides evidence that USgFNA offers a very sensitive and accurate method in reducing THY1 samples and in detecting malignancy (>95% both in THY5 and THY4, and >29% in THY3 lesions). Our proposal is to submit to total thyroidectomy all patients with THY5 and THY4 lesions and THY3 thyroid nodule >1 cm.

Liquid-based FNAC of the thyroid: a 4-year survey with SurePath

BACKGROUND

The aims of this study were to analyze cytomorphological features of Tripath PREP (BD SurePath, Burlington, NC) preparations in thyroid nodules and to examine adequacy and accuracy of SurePath and frozen sections for both clinical outcome and histological diagnosis when applicable.

METHODS

Gathered during a period of 4 years, 712 SurePath specimens of the thyroid were included. Histological (n = 207) or clinical follow-up (n = 505) was available in all cases. During the same period, 253 frozen sections of surgical thyroid resection specimens were also assessed. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated.

RESULTS

Sensitivity was 77% for SurePath and 29% for frozen section; specificity was 81% for SurePath and 100% for frozen section; accuracy was 80% for SurePath and 90% for frozen section. One hundred seventy-eight (25%) SurePath patients were considered unsatisfactory for diagnosis. In this study, sensitivity, specificity, and accuracy were comparable for SurePath and other reported results of liquid-based thyroid cytology. Presence of free colloid or pure cystic changes favored a benign diagnosis. Cellular smears with nuclear atypia of papillary carcinoma allowed an overt diagnosis of malignancy.

CONCLUSIONS

The authors concluded that SurePath is a reliable technique for assessment of thyroid nodules and offers the advantage of easy identification of colloid and atypical nuclei. Supplementary frozen section analysis should be limited to an FNAC diagnosis of suspicious for papillary carcinoma.

Diagnostic value of a cytomorphological subclassification of follicular patterned thyroid lesions: a study of 927 consecutive cases with histological correlation

BACKGROUND

Fine-needle aspiration cytology (FNAC) has proved to be an effective diagnostic tool in patients with thyroid nodules. Several reporting schemes have been suggested to define the risk of malignancy and consequent clinical management. To date, however, among lesions showing a follicular pattern, FNAC is still unable to differentiate between benign and malignant ones. The aim of our study was to evaluate whether a subclassification of follicular cytologic specimens, based on cytoarchitectural patterns, could differentiate categories with a different risk of malignancy, thus improving the clinical management of patients harboring follicular nodules.

METHODS

We report a cohort of 927 consecutive cases who underwent thyroid surgery in our hospital between 2000 and 2008. Each patient underwent FNAC before surgery. All the cytologic specimens were divided into five categories (Thy 1: inadequate material, Thy 2: benign, Thy 3: indeterminate, Thy 4: suspicious for malignancy, Thy 5: malignant). Thy3 specimens were further divided into three subcategories (Thy 3a, or "follicular lesions of indeterminate significance": scant colloid, microfollicular pattern, or small clusters of thyrocytes with round nuclei usually without, but sometimes with, minimal cellular pleomorphism; Thy 3b, or "follicular neoplasm": absence of colloid, small clusters, or microfollicles of medium-large sized cell populations arranged in cohesive groups with nuclear overlapping, crowding, and pleomorphisms; and Thy 3c or "Hurthle-cell neoplasm": scant colloid, sheets or clusters of oxyphilic cells).

RESULTS

Thy 1 specimens (51 cases on the whole) proved to be malignant in 5.88% (3 cases), Thy 2 specimens (319) in 3.45% (11 cases), Thy 4 specimens (91) in 84.62% (77 cases), and Thy 5 specimens (172) in 98.84% (170 cases). Thy 3 specimens (294 cases) proved to be malignant in 17.35% as a whole, but when divided into the three subcategories, the percentage of malignant cases was significantly different between the Thy 3a group (4.95%) and the Thy 3b and Thy 3c groups (25.0% and 22.77% respectively).

CONCLUSIONS

This study supports the National Cancer Institute consensus showing a different risk of malignancy for "follicular lesions of undetermined significance” compared with "follicular neoplasms" and "Hurthle cells neoplasms," which are more suspect for malignancy. This subclassification could improve clinical management of thyroid nodules, helping to better select patients for surgery or follow up.

Relevance of immunocytochemistry on thin-layer cytology in thyroid lesions suspicious for medullary carcinoma: a case-control study

BACKGROUND

Fine needle aspiration cytology represents the most important tool in the diagnosis of thyroid nodules, mostly in discriminating malignant from benign lesions. The diagnosis of medullary thyroid carcinoma (MTC) may present some problems related to its deceptive morphologic picture. This diagnosis may be supported by immunocytochemistry (ICC), which may be difficult to carry out on the conventional smears.

DESIGN

The diagnostic efficacy of ICC for the diagnosis of MTC with respect to other thyroid neoplasms on slides processed by thin-layer cytology (TLC) is evaluated.

PATIENTS

In the period between January 2002 and December 2005, 8,200 FNAB were processed. ICC on TLC slides was required in 33 cases. Conventional smears were fixed in ethanol, whereas TLC slides were processed with the Thin Prep 2000 method. All slides were then stained with Papanicolaou. In all cases where MTC was morphologically suspected, ICC for calcitonin, monoclonal carcinoembryonic antigen, and thyroglobulin was carried out only on TLC slides.

RESULTS

Thirty-three thyroid cytologic cases had ICC on the TLC slides, including 22 follicular proliferations and 11 malignant lesions. The application of ICC on TLC was conclusive in 32 cases and inconclusive in 1 case. Twenty cases underwent surgery. No false-positive and false-negative cases were found. Sensitivity and specificity were 100%, and the overall diagnostic accuracy was 100%.

CONCLUSIONS

ICC can be successfully applied on TLC slides. The combined results of morphology and a small immunopanel including thyroglobulin, calcitonin, and carcinoembryonic antigen yields a 100% diagnostic efficacy for MTC.

CONDENSED ABSTRACT

Fine needle aspiration cytology is an excellent technique for diagnosing malignant neoplasms of the thyroid, especially those derived from the follicular cells. A correct preoperative diagnosis of C-cell-derived tumors (MTC), which is essential for both the surgical approach to the primary tumor and the management of the patient, should rely not only on the morphologic picture but also on the immunocytochemical yielding using an immunopanel, which is particularly satisfactory on the TLC slides.

Techniques for thyroid FNA: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid fine-needle aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The 2-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters addressing manual and ultrasound guided FNA technique and related issues. Specific topics covered include details regarding aspiration needles, devices, and methods, including the use of core needle biopsy; the pros and cons of anesthesia; the influence of thyroid lesion location, size, and characteristics on technique; the role of ultrasound in the FNA of a palpable thyroid nodule; the advantages and disadvantages of various specialists performing a biopsy; the optimal number of passes and tissue preparation methods; sample adequacy criteria for solid and cystic nodules, and management of adverse reactions from the procedure. (http://thyroidfna.cancer.gov/pages/info/agenda/)

Fine needle aspiration cytology of thyroid nodules: conventional vs thin layer technique

OBJECTIVE

Liquid-based cytology using the thin layer technique has recently been introduced in thyroid fine needle aspiration cytology together with or in substitution of direct smears, but its usefulness is still controversial and relatively few studies have been published in this field. The aim of the present study was to compare the results obtained from conventional smears with those from thin layer smears.

DESIGN

In 3875 thyroid nodules, a double cytologic sampling was taken in randomized order, to prepare conventional or thin layer smears.

MAIN OUTCOME

The diagnoses agreed in 2934 (75.7%) cases and disagreed in 941 (24.3%). The analysis of discordant data showed there were fewer non-diagnostic cases in the thin layer smears (377 vs 541, p<0.001) whereas in conventional smears there were more cases positive for carcinoma (27 vs 4, p<0.001). The cytohistologic correlation was available for 194 cases and showed that conventional smears had a greater capacity for revealing carcinomas (44 vs 31). Finally, diagnoses based on conventional smears were more sensitive than thin layer smears (93.6% vs 65.9%) whereas specificity was constant.

CONCLUSIONS

From our experience, the conventional smear offers a greater possibility of diagnosis when suspecting malignancy or diagnosing malignancy cases, whereas thin layer smears significantly reduce the number of non-diagnostic cases. For this reason, we suggest combining the two techniques in routine cytologic diagnosis.

Comparison of Thin-Prep and cell block preparation for the evaluation of Thyroid epithelial lesions on fine needle aspiration biopsy

Background

The objective of this study was to compare the utility of Thin-Prep (TP) cytologic preparation with that of Cell Block (CB) preparation in the diagnosis of thyroid lesions, mainly follicular epithelial lesions, by fine needle aspiration biopsy (FNAB). Feasibility of using the TP slides for immunocytochemical stains is also discussed.

Methods

A total of 126 consecutive cases of thyroid FNAB with TP slides and 128 consecutive cases of thyroid FNAB with CB slides were reviewed blindly by two cytopathologists. The presence of colloid, follicular cells, macrophages and lymphocytes/plasma cells were recorded and scored 0–4 on each case based on TP or CB slide review. The cytologic diagnoses were grouped as follows: cyst, colloid nodule, colloid nodule with cystic change, chronic thyroiditis, atypical/neoplastic and non-diagnostic.

Results

The TP slides had higher diagnostic rate than CB slides. The diagnostic yield was 68% of the TP slides whereas only 24% of the CB slides were diagnostic. Also, only 4 atypical/neoplastic lesions were diagnosed on the TP slides and the corresponding direct smears, while 5 cases of atypical/neoplastic lesions were diagnosed on the smears but could not be diagnosed on the corresponding CB slides. Additionally, the TP slides revealed cytologic features that were not observed on the direct traditional smears of the same case.

Conclusion

In thyroid FNAB cases, TP slide preparation is superior to CB slide preparation and is more likely to have greater cellularity for diagnosis and detect atypical/neoplastic thyroid lesions, particularly those of follicular cell origin. Furthermore, TP slides appear to detect helpful diagnostic cytologic features and should be considered complementary to, rather than replacing, direct smears.

Long-term assessment of a multidisciplinary approach to thyroid nodule diagnostic evaluation

BACKGROUND

The diagnostic evaluation of patients with thyroid nodules is imprecise. Despite the benefits of fine-needle aspiration (FNA), most patients who are referred for surgery because of abnormal cytology prove to have benign disease. Recent technologic and procedural advances suggest that this shortcoming can be mitigated, although few data confirm this benefit in unselected patients.

METHODS

A total of 2587 sequential patients were evaluated by thyroid ultrasound and were offered ultrasound-guided FNA (UG-FNA) of all thyroid nodules that measured > or =1 cm during a 10-year period. Results of aspiration cytology were correlated with histologic findings. The prevalence of thyroid cancer in all patients and in those who underwent surgery was determined. Surgical risk was calculated.

RESULTS

Tumors that measured > or =1 cm were present in 14% of patients: Forty-three percent of patients had tumors that measured <2 cm in greatest dimension, and 93% had American Joint Committee on Cancer stage I or II disease. The cytologic diagnoses 'positive for malignancy' and 'no malignant cells' were 97% predictive and 99.7% predictive, respectively. Repeat FNA of initial insufficient aspirates, as well as more detailed classification of inconclusive aspirates, improved preoperative assessment of cancer risk and reduced surgical intervention. Fifty-six percent of patients who were referred for surgery because of abnormal cytology had cancer compared with from 10% to 45% of patients historically. An analysis of operative complications from a subset of 296 patients demonstrated a 1% risk of permanent surgical complications.

CONCLUSIONS

The current findings demonstrated the benefits of UG-FNA and of a more detailed classification of inconclusive aspirates in the preoperative risk assessment of thyroid nodules, supporting adherence to recently published guidelines.

Percutaneous large-needle aspiration biopsy histology of palpable thyroid nodules: technical and diagnostic performance

AIM

To report original and review existing data on safety and performance of large-needle aspiration biopsy (LNAB) histology in the preoperative selection of palpable thyroid nodule.

METHODS AND RESULTS

The English literature and original data were reviewed or analysed. The literature on LNAB of thyroid nodules did not report any complications. A study on needle dimensions has explained why LNAB obtains more tissue than fine-needle aspiration (FNA) and is safe. LNAB histology has higher specificity than FNA cytology and markedly reduces the number of inadequate and indeterminate FNA findings. A comparison of 150 FNA-derived cell blocks with 200 LNAB-derived histological blocks after galectin-3 determination in a large nationwide (Italian) study has shown that one to two sections in 10% of the FNA cell blocks and at least five sections in 90% of the LNAB blocks were available for further determinations of thyroid tumour markers.

CONCLUSION

LNAB merits further consideration for the preoperative selection of thyroid nodules.

Non-gynecologic cytology on liquid-based preparations: A morphologic review of facts and artifacts

Liquid-based preparations (LBP) are increasingly being used both for gynecologic (gyn) and non-gynecologic (non-gyn) cytology including fine needle aspirations (FNA). The two FDA-approved LBP currently in use include ThinPrep (TP), (Cytyc Corp, Marlborough, MA) and SurePath (SP), (TriPath Imaging Inc., Burlington, NC). TP was approved for cervico-vaginal (Pap test) cytology in 1996 and SP in 1999 and both have since also been used for non-gyn cytology. In the LBP, instead of being smeared, cells are rinsed into a liquid preservative collection medium and processed on automated devices. Even after a decade of use, the morphological interpretation of LBP remains a diagnostic challenge because of somewhat altered morphology and artifacts or facts resulting from the fixation and processing techniques. These changes include cleaner background with altered or reduced background and extracellular elements; architectural changes such as smaller cell clusters and sheets, breakage of papillae; altered cell distribution with more dyscohesion and changes in cellular morphology with enhanced nuclear features, smaller cell size and slightly more three-dimensional (3-D) clusters. Herein, we review the published literature on morphological aspects of LBP for non-gyn cytology.

Contemporary diagnostic approach to the thyroid nodule

Thyroid nodules are common, with an estimated incidence of 5%-10% in the United States. The current gold standard for diagnosis is fine needle aspiration biopsy (FNAB). The incidence of indeterminate diagnoses varies from 10% to 25%. Surgical resection is usually indicated to exclude the diagnosis of cancer in these patients. However, only a minority (about 20%) of indeterminate thyroid nodules actually harbor a malignancy, resulting in surgery for diagnostic purposes alone in many patients. The increased detection of benign nodules and microcarcinomas reinforces the need for improved non-operative methods to differentiate benign from malignant disease and discriminate low-risk from high-risk cancers. In this article we present a current, rational diagnostic approach to the patient with a thyroid nodule, evaluate new advances including thyroid genomic and predictor models, and propose the development of prospective trials to incorporate these new additions into clinical decision making. Given how many questions still exist for patients with thyroid nodules, partnership and collaboration, or the "bench to bedside" concept should find its way into most every thyroid surgeon and endocrinologist's lexicon.

Cellular swirls in fine needle aspirates of papillary thyroid carcinoma: a new diagnostic criterion

No single cytologic feature is specifically diagnostic for papillary thyroid carcinoma. We report herein the presence of swirl-like cellular aggregates in fine needle aspirates of papillary thyroid carcinoma but not in other thyroid entities. Cellular swirls are defined as concentrically organized aggregates of tumor cells in which many of the most peripherally situated cells have ovoid rather than round nuclei that are oriented perpendicular to the radius of the swirl. One hundred Papanicolaou- and/or Diff-Quik-stained FNAs of the thyroid diagnosed as papillary carcinoma, including seven fine needle aspirates of cervical lymph nodes showing metastatic papillary carcinoma, with or without cell blocks, were reviewed for the presence of cellular swirls. An additional 100 thyroid FNAs, similarly stained and prepared, diagnosed as nodular goiter, Hashimoto's thyroiditis and follicular neoplasm were also reviewed for the presence of cellular swirls. Cellular swirls were easily observed at screening magnification and confirmed at high magnification. Seventeen of 100 FNAs (17%) of papillary carcinoma contained cellular swirls. No cases diagnosed as nodular goiter, Hashimoto's thyroiditis or follicular neoplasm contained these structures. Thirteen cases with swirls had histologic follow-up. These comprised seven papillary carcinomas with classical histopathology, two designated 'differentiated papillary carcinoma,' two with follicular variant histopathology; one with a minor component of follicular variant histopathology; one papillary carcinoma metastatic to a cervical lymph node with classic histopathology. Swirls occurred in cases with relatively little pleomorphism, or in well-differentiated regions of papillary carcinoma that also displayed less well-differentiated components. Cellular swirls are a finding that is highly specific to papillary thyroid carcinoma. They are easily seen at screening magnification. Their presence in a FNA specimen may be helpful in cases where classic criteria for papillary thyroid carcinoma are scarce, particularly in well-differentiated papillary thyroid carcinoma. While the size and scope of this study are insufficient to conclude that cellular swirls alone are diagnostic of papillary thyroid carcinoma in the absence of other criteria, we believe these structures should be added to the list of diagnostic criteria.

Fine-needle aspiration biopsy of thyroid lesions processed by thin-layer cytology: one-year institutional experience with histologic correlation

Fine-needle aspiration biopsy (FNAB) is important for classifying thyroid lesions. Thin-layer cytology (TLC) has been adopted in thyroid cytology with encouraging results and its efficacy in diagnosing nodular lesions in a 1-year period was evaluated. All 2006 thyroid FNAB processed by TLC only in the year 2004 were examined. The 2002 and 2003 series, processed both by TLC and conventional smears (CS), were used as controls. All FNAB were classified according to previously published morphologic criteria. Surgery was performed on 311 cases: all 98 benign and 30 malignant lesions were histologically confirmed. The inadequate diagnoses resulted 11.3% in 2004, 13.3% in 2003, and 18.2% in 2002. The indeterminate diagnosis rate was 16.9% in 2004, 20.7% in 2003, and 24.8% in 2002. Sensitivity, specificity, and diagnostic accuracy values ranged from 80% to 100%. TLC is useful in reducing inadequate and indeterminate cases without decreasing the preoperative diagnostic accuracy. Ancillary techniques can be successfully applied to the stored material.

Immunocytochemical evaluation of thyroid neoplasms on thin-layer smears from fine-needle aspiration biopsies

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is the most reliable diagnostic tool for thyroid nodules. A difficult cytologic diagnosis may be supported by an immunocytochemical study. The efficacy of a panel made up of RET, HBME-1, and Galectin-3 antibodies was evaluated in smears processed by thin-layer cytology (TLC).

DESIGN

Thyroid FNABs (n = 99) with both conventional (CS) and thin-layer cytology (TLC) smears were studied. The cases were diagnosed as follows: 5 benign lesions (BL), 13 papillary carcinomas (PC), and 81 follicular proliferations (FP). The category of FP was divided into three subgroups according to nuclear features of follicular cells: Follicular neoplasm (FN NOS), oxyphilic follicular neoplasm (OFN), and follicular lesion with nuclear pleomorphism (FLWNP). Immunostains for HBME-1, Galectin-3, and RET were carried out on TLC slides.

RESULTS

Among 49 cases undergoing surgery, all 10 PC and 2 BL were histologically confirmed, whereas 15 out of 37 FP (40.5%) were malignant. The complete immunocytochemical panel (ICCP) was positive in 9 of 10 malignancies (90%) and negative in both BLs. Out of 37 FP, the ICCP yielded positive in 15 cases (4 benign, 11 malignant) and negative in 11 (all benign). In the FLWNP subgroup, the ICCP was positive in 11 (84.6%) and negative in 2 histologically benign cases.

CONCLUSION

The combined panel of antibodies and the nuclear pleomorphism of follicular cells were effective in distinguishing between thyroid nodules requiring surgery from thyroid nodules requiring just follow-up.

Reporting thyroid fine-needle aspiration: Literature review and a proposal

Reporting schemes for thyroid fine-needle aspirations in the literature were reviewed and classified according to the number of categories in the scheme and the significance of each category. The sensitivity, specificity, and positive predictive and negative values were determined for each scheme, if possible. A reporting scheme based on the probability of finding carcinoma on histology is proposed.

Comparison of ThinPrep and conventional preparations in pancreatic fine-needle aspiration biopsy

Use of ThinPrep preparation for fine-needle aspiration biopsy (FNA) is gaining popularity. However, there may be a difference in the morphology and the operating characteristics between ThinPrep and conventional methods. The objective of this study was to compare the accuracy of the two methods and to address the pitfalls of ThinPrep preparation in pancreatic FNA. A computer search identified 67 pancreatic FNAs with both conventional smears and ThinPrep preparation during a 19-mo period. These cases, obtained under endoscopic ultrasound-guidance, consisted of 47 malignant neoplasms (44 ductal carcinomas, two mucinous neoplasms, and one islet cell tumor) and 20 benign lesions. Direct smears were prepared first and the remaining material was then put into PreservCyt Solution for ThinPrep slides. All slides were reviewed and the cytologic diagnoses were correlated with histologic and clinical follow-up. Five conventional and 16 ThinPrep specimens were unsatisfactory due to insufficient cellularity. These cases were excluded from the analysis. Among the 62 cases evaluated by conventional preparation, 77% (34) were diagnosed as positive and 14% (seven) atypical/suspicious by conventional smears. For the 51 ThinPrep specimens, 58% (22) were interpreted as positive and 31% (12) atypical/suspicious. The sensitivity, specificity, and accuracy of diagnosing a malignancy were 77%, 100%, and 84% for conventional smears and 58%, 100%, and 67% for ThinPrep preparation, respectively. There were no false positives with either method. However, three benign lesions were interpreted as atypical/suspicious with ThinPrep preparation because of the presence of single atypical cells with distinct nucleoli. One of the two mucinous neoplasms was incorrectly diagnosed with ThinPrep preparation because of lack of mucin. The diagnostic accuracy of pancreatic FNA using ThinPrep is inferior to that of conventional smears. This may be partly due to the use of split sample technique resulting in scant cellularity in ThinPrep preparation and partly due to the differences in morphology between the two preparations. Therefore, the current morphologic criteria may need modification for ThinPrep preparation in pancreatic FNA.

ThinPrep® for cytologic evaluation of follicular thyroid lesions: Correlation with histologic findings

Fine needle aspiration (FNA) is often the first step in management of a thyroid nodule. Although papillary carcinomas have distinctive features on conventional smears as well as ThinPrep preparations, cytopathologists rely on the architectural arrangement of cells to classify follicular lesions. The accuracy of ThinPrep in this regard has not been determined. We reviewed all thyroidectomy specimens from a 22-mo period that showed a follicular lesion and had one or more preoperative FNA. The architecture of the lesions on histology was classified as predominantly (>70%) macrofollicular (MA), predominantly microfollicular (MI), mixed (MX), or cystic (C). The presence of colloid, Hürthle cell features, cystic change, Hashimoto's thyroiditis, and nonspecific lymphocytic thyroiditis were also recorded. All FNA specimens were processed with the ThinPrep(R) method and were categorized as nondiagnostic, benign (MA or MX), indeterminate (due to suboptimal cellularity), or suspicious (consistent with a microfollicular or Hürthle cell neoplasm) based on cellularity, architectural arrangement of the follicular cells, and the presence or absence of colloid on FNA. Those cytologic specimens in the indeterminate category were subcategorized as suggestive of an MA, MX, or MI lesion if possible. Histocytologic findings were correlated using Fisher's exact test. A total of 95 patients with 115 FNAs were included in the study (mean age: 48 yr; 75 females and 20 males). Seven of the FNAs were nondiagnostic, 23 benign, 69 indeterminate (5, 8, and 30 favor MA, MX, and MI, respectively, 6 cyst contents and 20 not subclassifiable) and 16 suspicious. The cytohistologic correlation for architecture was significant (P = 0.003). The cytohistologic correlation of cystic change, Hürthle cell change, and the presence of colloid (large fragments of colloid and "tissue-paper-like material" on cytology vs. abundant colloid on histology) was highly significant (P < 0.001, < 0.001, and < 0.03, respectively). In conclusion, thyroid FNA with ThinPrep is useful in predicting the architectural pattern of follicular lesions. It is also reliable in predicting cystic change, Hürthle cell change, and the presence of colloid. Watery colloid is probably present as "tissue-paper-like material" in thyroid FNA ThinPrep preparations.

Thyroid fine needle aspiration: the morphological features on ThinPrep® slide preparations. Eighty cases with histological control

This study had several purposes: to define cytomorphological features of thyroid cells that might be modified by alcohol fixation; to optimize May-Grünwald-Giemsa (MGG) staining on ThinPrep(R) (TP; Cytyc Inc., Bexborough, MA, USA) slides and to compare the diagnostic accuracy of slides prepared by a liquid-based method with those obtained by conventional technique. This study included 120 cases of ultrasound-guided fine needle aspiration (FNA) of the thyroid and 55 FNAs performed on surgically resected thyroid specimens. Histological control was available in 80 cases. In the first group of 120 FNAs, a split-sample technique was used for the TP. Three screenings were performed: first, an individual screening of the conventional smears (CS) and of the TP, a second screening to compare cells observed on the TP with the histological control and a third screening to assess the previously defined diagnostic criteria. Twenty-seven TP cases (22%) were considered unsatisfactory for diagnosis compared with 10 in CS (8%). The high rate of unsatisfactory cases with TP is likely to be due to the use of the split-sample technique. The sensitivity was 94% for CS and 81% for TP. The specificity was 67% and 60% for CS and TP, respectively. Two occult papillary carcinomas were missed by both methods. As for the MGG staining, the modified technique used for TP resulted in the same quality as the standard procedure. Conversely, TP did however induce uncommon morphological features. In this study, sensitivity and specificity levels are higher for CS than for TP; the difference may be explained by the fact that the methanol fixative used for TP induces some cytological alterations, especially in oncocytic tumours and lymphocytic thyroïditis.

Cytologic features of small-cell carcinoma on ThinPrep

The use of ThinPrep (TP) technology for fine-needle aspiration (FNA) cytology has become widely accepted. However, some literature suggests that small-cell carcinoma may present a diagnostic pitfall due to morphologic alterations. In this study, we retrospectively compared 14 FNA of small-cell carcinoma prepared using TP with corresponding conventional smears (CS). We also examined the TP appearance of 23 other small round-cell lesions in order to determine if differential diagnostic features were preserved. TP and CS were evaluated semiquantitatively for background, architecture, chromatin quality, nuclear molding, nuclear smearing, nucleolar prominence, amount of cytoplasm, nuclear size, and single-cell necrosis. The data were analyzed using the McNemar chi(2) test. TP slides of small-cell carcinoma showed a cleaner background than CS (P < 0.005). Although some degree of nuclear molding was preserved, it was decreased in amount (P < 0.025) and subtler in quality. Similarly, nuclear smearing was present but decreased in amount (P < 0.05), and less prominent qualitatively. The amount of discernible cytoplasm was greater on TP (P < 0.005). No significant differences were found for any of the other parameters studied. The presence of nuclear molding was the single most useful feature in differentiating small-cell carcinoma from other small round-cell tumors on TP. Small-cell carcinoma may be diagnosed with confidence by FNA using TP. However, pathologists should be aware of certain morphologic alterations in order to avoid diagnostic pitfalls.

Selected problems in fine needle aspiration of head and neck masses

A wide variety of masses in the head and neck, including those in the major salivary glands, can be approached by fine needle aspiration. In many instances, a correct definitive diagnosis con be rendered after examination of smears or cell block material. However, several significant but uncommon areas can lead to diagnostic difficulties, with the potential for clinically important diagnostic errors. Many of these occur in salivary gland lesions. The most frequent problems involve variations in the expected cytology of pleomorphic adenoma. Then, there are several benign-malignant "look-alike" pairs of lesions. The first of these is related to small-cell epithelial neoplasms of low nuclear grade; the most frequent problem is between basal cell adenomas and adenoid cystic carcinoma, particularly the solid (anaplastic) type. The next area contrasts mucoepidermoid carcinoma with its cytologic mimic, benign salivary gland duct obstruction. The final difficulty in salivary gland aspiration contrasts large-cell epithelial lesions of low nuclear grade: oncocytic proliferations and acinic cell carcinoma. The clinical implications of cytologically benign squamous cell-containing cyst aspirates from the lateral neck will be discussed. Finally, a brief consideration of methodological optimization for thyroid aspirations will be offered.

Comparison of ThinPrep and TriPath PREP liquid-based preparations in nongynecologic specimens: a pilot study

ThinPrep (TP) and TriPath PREP (TriP) are two liquid-based cytologic preparations that produce a thin layer of cells. This study compares the diagnostic accuracy and different cytomorphologic alterations produced by these preparations in nongynecologic specimens. Samples from 10 urines (3 urothelial carcinomas and 7 negative), 4 positive serous fluids, and 7 fine-needle aspirates (FNAs) were prepared by both techniques. FNAs represented one each of: Hashimoto's thyroiditis (HT), hyperplastic colloid nodule (HCN), Hodgkin's lymphoma, liposarcoma, chondrosarcoma, squamous-cell carcinoma (SCC) metastatic to the lymph node, and carcinoid tumor. All 5 participants, none of whom had prior knowledge of the clinical history or histologic diagnosis, reviewed and interpreted the slides. Both techniques produced a clean background and were equally accurate in urines, serous fluids, and three FNAs. TriP was slightly more accurate in four FNAs: HCN and HT where colloid and lymphocytes were better represented, SCC where keratin and malignant cells were more readily identified among lymphocytes, and carcinoid which was easier to evaluate on TriP due to less cellular shrinkage and more dispersion of cells between aggregates. TP preparations had more cell shrinkage, and the chromatin was harder to evaluate. Both techniques produced artificial aggregations of lymphocytes, but TriP had a more evenly dispersed single-cell population between aggregates, rendering them easier to evaluate for atypia. TP produced fragmentation of large sheets that were flattened, while TriP contained larger branching sheets in a three-dimensional (3-D) configuration. TP produced a true monolayer of cells that were all spread at the same plane, while in TriP the cells were spread at slightly different planes, requiring frequent focusing of the viewed plane. While both techniques are acceptable for diagnostic purposes, they both introduce new cytomorphologic alterations that pathologists need to recognize. TriP seems superior to TP in FNAs specimens where preservation of architecture and cellular integrity are important considerations.

Morphologic predictors of papillary carcinoma on fine-needle aspiration of thyroid with ThinPrep preparations

Although the cytologic features of papillary carcinoma of the thyroid are well-known, none is entirely specific. We conducted this study to determine the minimal criteria necessary to achieve 100% specificity for the diagnosis of papillary carcinoma on fine-needle aspiration (FNA). Forty patients with histologically confirmed papillary carcinoma and 17 patients with other thyroid lesions who underwent preoperative FNA at Beth Israel Deaconess Medical Center during a 4-yr period were included in the study. All cytology slides were prepared with the ThinPrep processing technique. Various architectural and nuclear features were evaluated, with a score assigned to each feature, and correlated with the histologic diagnosis of papillary carcinoma. Intranuclear inclusions, papillary and/or sheet arrangements, nuclear grooves, powdery chromatin, nuclear molding, high cellularity, and small nucleoli were significantly associated with papillary carcinoma (P < 0.05). The requirement of any intranuclear inclusions and many nuclear grooves, or a minimum of sum of scores (of the above eight features) of 10, yields 100% specificity and approximately 70% sensitivity. Cases with fewer features can be reported as suspicious or indeterminate for papillary carcinoma. A quantitative/probabilistic approach in the reporting of thyroid FNA provides a practical guide for management of patients with thyroid nodules.

Analysis of ret/PTC gene rearrangements refines the fine needle aspiration diagnosis of thyroid cancer

Papillary carcinoma (PC) represents the most common malignancy of the thyroid gland. Therefore, the assessment of fine needle aspiration biopsies of thyroid nodules rests heavily on the identification of nuclear features of PC. The ret/PTC oncogene, formed by several gene rearrangements, is specific for PC among thyroid tumors. In this study we examined thyroid aspirates for the presence of ret/PTC gene rearrangements by RT-PCR and Southern hybridization. We prospectively collected thyroid aspirates in Cytolyt solution and prepared slides for cytological examination using the ThinPrep method. All remaining material was then used for nucleic acid extraction with subsequent RT-PCR for the housekeeping gene PGK-1 to ensure ribonucleic acid integrity, for thyroglobulin to ensure the presence of follicular epithelial cells, and for the three most common ret/PTC gene rearrangements (ret/PTC-1, -2, and -3). The results of the first 73 cases with surgical follow-up were correlated with the cytological diagnosis and final histopathology. ret/PTC gene rearrangements were detected in 17 of 33 samples (52%) that were PC on histopathology; the presence of gene rearrangements was confirmed by molecular analysis of corresponding surgically resected frozen tissue. There were no false positives. The identification of ret/PTC gene rearrangements refined the diagnosis of PC in 9 of 15 specimens (60%) that would otherwise have been considered indeterminate and in 2 of 6 that were considered insufficient for cytological diagnosis. The results indicate that RT-PCR for ret/PTC is a specific marker that can be applied to fine needle aspiration biopsies and improves the diagnosis of malignancy when used as an adjunct to traditional cytology.

Diagnostic value of liquid-based (Thinprep) preparations in nongynecologic cases

Most studies utilizing the liquid-based ThinPrep method for the preparation of nongynecological specimens report a diagnostic sensitivity and specificity of over 90%. ThinPrep-processed slides in 162 cases sent to us from outside laboratories were assessed for their diagnostic value. These included fine-needle aspiration (FNA) (128) and other nongynecological specimens (34), representing bronchopulmomary washings, body cavity fluids, and urine samples. Slides were examined independently for adequacy and diagnostic value. These results were compared with the final diagnosis rendered upon examination of the entire submitted cytologic specimens, including direct smears, cytospins, and cell blocks. Based on review of the ThinPrep-processed slides alone, diagnosis of malignancy or neoplasia was made in 54 of 86 cases (63%), while 18/86 (21%) were less than optimal and 14/86 (16%) were unsatisfactory. Pulmonary specimens, body cavity fluids, and urine were generally satisfactory, while thyroid and breast FNA were more often less than optimal or unsatisfactory. This limited study suggests that utilization of ThinPrep processing alone may have reduced diagnostic value in the fine-needle aspiration cases studied here.

Interpretation of fine-needle aspirates processed by the ThinPrep technique: cytologic artifacts and diagnostic pitfalls

The improvement in quality of cytologic preparations with the use of the ThinPrep methodology has been well-documented, but the cytologic artifacts resulting from this technique have not been adequately described. This study describes and illustrates the cytologic artifacts introduced by the ThinPrep technique when used on fine-needle aspirates (FNAs), and evaluates these artifacts as potential diagnostic pitfalls. We reviewed a total of 120 FNAs simultaneously processed by both conventional smears and ThinPrep. FNAs were obtained from the following sites: lymph node (27), breast (23), soft-tissue sites (20), salivary glands (13), gastrointestinal tract (10), lung (9), thyroid gland (13), liver (3), adrenal gland (1), and kidney (1). The ThinPrep smears were consistently devoid of obscuring elements, and the cells were adequately preserved and evenly dispersed. However, we noted some cytomorphologic alterations that should be recognized to avoid erroneous diagnoses. The size of cell clusters was decreased, large branching sheets were fragmented, and there were more single cells, resulting in apparent discohesion. Small cells such as lymphocytes tended to aggregate. All cells were generally smaller and occasionally spindled, the chromatin detail was attenuated, and nucleoli were more prominent. Intranuclear inclusions were difficult to visualize. Background matrix was often altered in both quantity and quality. Extracellular particles, small mononuclear cells, red blood cells, and myoepithelial cells were markedly decreased in number. The pathologist should be cautious in interpreting FNAs prepared using ThinPrep if that is the only methodology employed. Familiarity with artifacts is essential to avoid misinterpretations.

Thin layer compared to direct smear in thyroid fine needle aspiration

The efficacy of preparing thyroid fine needle aspirations (FNAs) by the thin layer as opposed to the direct smear method has not been evaluated sufficiently in a regional laboratory setting. At the Foothills Hospital (Calgary, Canada), the method of processing thyroid FNAs was changed from direct smear to thin layer in January 1996. The results of 327 patients who had direct smear from 1994 to 1995 were compared to 401 who had thin layer between 1996 and 1997. While there were no significant differences across a broad range of quality indicators, thin layer showed a trend towards a higher proportion of true benign diagnoses (31% vs 24%), a lower proportion of inadequate specimens (41% vs 50%) and, most importantly, a lower false negative rate (3% vs 9%). In conclusion, the changeover to thin layer did not compromise the interpretation of thyroid FNAs.