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

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.

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.

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.

Molecular analysis of residual ThinPrep material from thyroid FNAs increases diagnostic sensitivity

BACKGROUND

Molecular testing for genetic alterations associated with malignancy is a potential triage approach for thyroid fine-needle aspiration (FNA) samples with indeterminate cytology. Because liquid-based FNA material allows for efficient RNA extraction, the authors analyzed residual material for common point mutations and rearrangements.

METHODS

Thyroid FNAs were classified according to The Bethesda System for Reporting Thyroid Cytopathology after routine ThinPrep slide preparation. Residual samples from malignant and indeterminate cases were submitted for molecular analysis, along with a random cohort of nondiagnostic and benign aspirates. Blinded analysis of BRAF and RAS point mutations and RET/PTC and PAX8/PPARγ rearrangements was correlated with subsequent follow-up.

RESULTS

Adequate results were obtained in 402 of 597 cases (67%). Mutations or rearrangements were detected in 24 of 117 cytologically indeterminate specimens (21%) (17 RAS rearrangements, 6 BRAF rearrangements, and 1 PAX8/PPARγ rearrangement). BRAF mutations were preferentially associated with malignant cytologic diagnoses (22 of 42 cases; 52%), with less frequent detection in the suspicious for malignancy category (4 of 27 cases; 15%) and very low detection in all other categories (1%-4%). Surgical follow-up confirmed malignancy in all 21 BRAF-mutated cases, 42% of RAS-mutated cases (10 of 24 cases), and 37% of cases with no detected mutation (39 of 105 cases).

CONCLUSIONS

Molecular analysis is feasible on residual ThinPrep material with the advantage of not requiring additional FNA procedures. The majority of BRAF mutations are identified in cases classified cytologically as malignant, and, to a lesser extent, as suspicious for malignancy. The usefulness of BRAF testing is limited by the low rate of BRAF-positive cases in other categories, thereby highlighting the need to identify other genetic drivers of clinically aggressive thyroid cancers.

'Suspicious for papillary thyroid carcinoma' before and after The Bethesda System for Reporting Thyroid Cytopathology: impact of standardized terminology

BACKGROUND

The high-risk 'suspicious for papillary thyroid carcinoma' (SPTC) is a clinically relevant diagnosis in the cytological interpretation of thyroid aspirates. While The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has provided invaluable terminology standardization, a performance comparison for this diagnostic category has not been performed. Therefore, this study evaluates the SPTC diagnosis before and after the introduction of TBSRTC in a large meta-analysis and at a single institution.

MATERIALS AND METHODS

The meta-analysis analyzed publications of SPTC or similar diagnoses before and after the introduction of TBSRTC. Similarly our own institutional experience was analyzed for the 8 years surrounding the introduction of TBSRTC. A correlation of the cytopathology and surgical pathology diagnoses was performed.

RESULTS

The introduction of TBSRTC coincided with a significant decrease in the fraction of cases called SPTC in the meta-analysis (4.5-3.1%, p < 0.00001) and in the institutional review (1.7-0.9%, p = 0.005). Meanwhile, the malignancy risk for those cases increased significantly in the meta-analysis from 62.5 to 80.5% (p < 0.00001) and trended upwards in the institutional review from 69 to 79% (p = 0.4). The follow-up rate was similar in both time periods in the meta-analysis and the institutional review.

CONCLUSIONS

The introduction of TBSRTC coincided with a decrease in the fraction of cases called SPTC and an increase in the malignancy risk associated with that diagnosis.

Fine needle aspiration cytology of nodular thyroid lesions: a 2-year experience of the Bethesda system for reporting thyroid cytopathology in a large regional and a university hospital, with histological correlation

OBJECTIVE

Thyroid fine needle aspiration (FNA) contributes to the appropriate management of nodular thyroid lesions. The introduced categories in the Bethesda system for reporting thyroid cytopathology (TBSRTC) are associated with an implied cancer risk, providing a clinical management guideline. This study aims to evaluate the reproducibility of this implied risk and to compare the results from two different cytopathology departments.

METHODS

Five hundred histologically confirmed FNAs, studied since the introduction of TBSRTC, were obtained from 4208 and 3587 FNAs performed in a large regional hospital in Herakleion, Crete (group A) and a university hospital in Athens (group B), respectively. Reports were issued according to TBSRTC. Aspirates were prepared with ThinPrep(®) and evaluated by two experienced cytopathologists. The reproducibility and accuracy were evaluated.

RESULTS

The proportion test for suspicious for malignancy (SFM) and malignant (M) cytology reports (P < 0.0001), and the number of malignancies on histology (P < 0.0001), were significantly higher in group A than in group B, consistent with a higher incidence of thyroid carcinomas in southern Greece. Although the malignancy rates were higher in group A than in group B for all categories, except M (A, 99.3%; B, 100%), the difference was only significant for benign aspirates (P = 0.0303). Malignancy rates for all categories in group A were above the TBSRTC recommended range, but were consistent with an increased prevalence of malignancy in that centre, differences in reporting practice and the variable ranges reported in the literature. There was lower sensitivity (P = 0.019) and overall accuracy (P = 0.003) in group A relative to group B, but no difference in specificity.

CONCLUSIONS

TBSRTC provides valuable information for the appropriate management of nodular thyroid lesions, both in a university and a large regional hospital.

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

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/)

The thyroid gland: recurring problems in histologic and cytologic evaluation

Nodules of the thyroid gland are frequently encountered, occurring in up to 7% of the population, and although most of these nodules are benign, carcinomas of the thyroid gland are the most common malignancy of the endocrine system. Although the different types of thyroid carcinoma are few, a wide variety of recurring problems exists in both their histologic and cytologic evaluation. Here, I will review a selected group of problematic areas, including unusual histologic variants of follicular adenoma, criteria for diagnosing minimally invasive follicular carcinoma, the use of fine-needle aspiration as a screening test for follicular neoplasia, challenging variants of papillary carcinoma, and features of poorly differentiated carcinoma.

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.

The role of liquid-based cytology in the investigation of thyroid lesions

OBJECTIVE

This study investigates the role of liquid-based cytology by ThinPrep technique in the detection of thyroid lesions.

METHODS

In all, 252 specimens from 157 patients for pre-operative evaluation of thyroid nodules, prepared by the ThinPrep, were examined. In all cases thyroidectomy followed the initial cytological evaluation. All cytological diagnoses were correlated to the histological ones.

RESULTS

According to our findings, a sensitivity of 87.80%, a specificity of 99.50%, a positive predictive value of 97.30%, a negative predictive value of 97.56% and an overall accuracy of 97.52% were observed in fine needle aspiration cytology in correlation to the histological diagnosis after thyroidectomy.

CONCLUSIONS

ThinPrep technique is a valid method for the pre-operative cytological diagnosis of thyroid nodules, offering the possibility of ancillary techniques, such as immunocytochemical and molecular methods and can, therefore, be potentially complementary to histological evaluation for further investigation of follicular lesions.

Thyroid FNAC cytology: can we do it better?

This article reviews recent developments in thyroid fine needle aspiration cytology (FNAC). While thyroid nodules are common, carcinoma is comparatively rare. Although histological assessment is used in most studies as the benchmark, the differential diagnosis on cytology or histology is not always reproducible. The literature shows wide variations in criteria for inadequate thyroid FNAC and study inclusion or exclusion criteria. In-clinic assessment of specimen adequacy and in-clinic reporting of thyroid FNAC has become popular although the costs and resource implications of in-clinic thyroid FNAC assessment and reporting are substantial. Many centres continue to use conventional techniques although liquid-based cytology and ultrasound-guided FNAC are gaining in popularity. Standardized categorical systems for FNAC reporting can make results easier to understand for clinicians and give clear indications for therapeutic action. Multidisciplinary case review is also essential, especially when there is diagnostic uncertainty. While currently of limited use, molecular pathology testing holds out some promise for the future.

Hyalinizing trabecular adenoma—an uncommon thyroid tumor frequently misdiagnosed as papillary or medullary thyroid carcinoma

BACKGROUND

Hyalinizing trabecular adenoma (HTA) is an uncommon benign thyroid tumor that can present as a solitary thyroid nodule, a prominent nodule in a multinodular goiter, or as an incidental finding in a thyroidectomy specimen. The clinical significance of the lesion is that it is frequently misdiagnosed as papillary carcinoma on fine-needle aspiration cytology or as papillary or medullary carcinoma on histopathological section. We reviewed our recent experience with 7 patients diagnosed with HTA.

METHODS

Fine-needle aspiration biopsy was performed in 7 patients presenting with a solitary thyroid nodule (n = 4) or a multinodular goiter (n = 3). The patients underwent total thyroidectomy (n = 6) or hemithyroidectomy (n = 1).

RESULTS

In 4 patients, the preoperative cytology was suggestive of papillary carcinoma, in 2 patients suspicious, and in 1 patient positive for papillary carcinoma. On histopathological section, 2 patients had a microscopic HTA, 2 patients had HTA in 1 or 2 nodules of a multinodular goiter, and 3 patients had HTA in a solitary nodule. Except in 1 patient, who had a microscopic focus (3.2 mm) of papillary carcinoma, there was no evidence of malignancy in the surgical specimens on permanent histopathological section.

CONCLUSIONS

Although HTA is a rare condition of the thyroid, the surgeon needs to be aware of this entity to be able to better discuss the pathological findings with the patient, particularly since some pathologists and endocrinologists believe that HTA may represent a malignant neoplasm of low metastatic potential.

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.

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.

Fine-Needle Aspiration Biopsy Findings Suspicious for Papillary Thyroid Carcinoma: A Review of Cytopathological Criteria

OBJECTIVES/HYPOTHESIS

The objective was to evaluate the usefulness of standard suspect cytological features on fine-needle aspiration biopsy (FNAB) in predicting papillary thyroid carcinoma.

STUDY DESIGN

Retrospective chart review of consecutive fine-needle biopsies of the thyroid.

METHODS

The study was a retrospective review of consecutive patients presenting with a diagnosis of suspected (group 1) or positive papillary thyroid carcinoma (group 2). The frequency of standard cytological features (i.e., papillary architecture, multinucleated giant cell, nuclear pseudo-inclusions, nuclear grooves, micronucleoli, powdery chromatin, and psammoma bodies) were recorded for each group. These were compared using chi test. Sensitivity and specificity for both individual and a combination of features were calculated for patients in group 1.

RESULTS

One hundred eight patients were eligible for the study (group 1, n = 57; group 2, n = 51). Fifty-one patients (89%) in group 1 and all patients in group 2 had a histopathological diagnosis of papillary thyroid carcinoma. Respectively, the most frequent features present on fine-needle aspiration biopsy in group 1 versus group 2 were nuclear grooves (79% vs. 88%), micronucleoli (74% vs. 86%), pseudo-inclusions (58% vs. 88%), and powdery chromatin (47% vs. 59%); P values for these features were P > .05, P > .05, P < .05, and P > .05, respectively. In group 1, the sensitivities of nuclear grooves and micronucleoli were 80% and 71%, respectively. The presence of psammoma bodies was associated with a specificity of 100%. A combination of nuclear grooves, micronucleoli, pseudo-inclusions, powdery chromatin, and multinucleated giant cells was 100% specific in detecting papillary thyroid carcinoma.

CONCLUSION

In choosing the most appropriate management of a finding suspect for papillary thyroid carcinoma on fine-needle aspiration biopsy, the surgeon must be aware of the diagnostic importance of certain cytopathological features. The presence of a combination of these factors may allow a more confident surgical approach.

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.