Liquid-based vs. conventional smears in fine needle aspiration of bone and soft tissue tumors

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.

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

BACKGROUND

Fine-needle aspiration (FNA) plays a pivotal role in the initial evaluation of patients with thyroid nodules. Traditionally, aspirated material is expelled directly onto the microscope slide to make a conventional smear (CS). Recently, liquid-based preparations (LBP) have gained in popularity. This study compares the accuracy of these two preparation techniques in diagnosing thyroid nodules.

METHODS

A clinical database containing 5475 thyroid cytology consults from 2009 to 2013 was queried to identify 5169 CS and 306 LBP cases. Cytological diagnostic frequency rendered before and after second review were compared between LBP and CS. Correlation with the histology diagnosis was also calculated for each preparatory technique.

RESULTS

Age, sex, and nodule size were comparable between patients who had FNA processed by LBP and CS. More LBP cases than CS cases were inadequate (17% vs. 10%; p<0.001). LBP cases had fewer benign diagnoses (39% vs. 47%; p=0.003) and tended to have more malignant diagnoses (16% vs. 12%; p=0.09) when compared to CS. Indeterminate and suspicious categories were comparable between LBP and CS. Correlation with histology was also comparable between both techniques.

CONCLUSION

LBP was associated with a significantly higher proportion of inadequate and a lower proportion of benign diagnoses. Thus, universal adoption of LBP may introduce more inadequate samples. Future investigations should explore the lack of on-site evaluation with LBP as a potential source for the high inadequate rate.

[Cytologic diagnosis of sarcoma]

Soft tissue swelling represents a common clinical sign of a variety of neoplastic and non-neoplastic lesions. Sarcoma is rarely a cause. Fine needle biopsy as a minimally invasive, economic and accurate method is well suited for the diagnosis of inflammatory/infectious processes as well as of recurrent and metastatic disease. Cytologic diagnosis of primary soft tissue tumors is also feasible. It requires close collaboration with other medical disciplines and incorporation of clinical, radiological and morphologic findings. Clinical data such as age, gender, size and topography are important parameters. The differentiation of cells and properties of the extracellular matrix supplies clues for the differential diagnosis and forms the starting point for immunohistochemical or molecular analysis (FISH, RT-PCR). This analysis may be performed on cytological smears, paraffin embedded material of the cell blocks or on frozen material.

Biopsy of soft tissue masses: evidence-based medicine for the musculoskeletal tumor society

The literature contains a number of controversies regarding key questions: (1) When is a biopsy indicated? (2) How should the biopsy be placed? (3) How should the biopsy be performed and which has the greatest diagnostic accuracy? (4) Who should perform the biopsy? (5) What clinical parameters present the greatest diagnostic difficulty? Using PubMed and Google Scholar we performed English-language literature searches of clinical studies reporting biopsy of soft tissue masses. Thirty-two studies met the inclusion criteria but were only able to address three of the five questions the authors had hoped to evaluate. Available evidence suggests open biopsy has the highest diagnostic accuracy over core needle biopsy, which was higher than fine needle aspiration. There was no evidence to address who is best suited to perform the biopsy (general surgeon, orthopaedic surgeon, radiologist, pathologist) in terms of accuracy of diagnosis. Frozen section at the time of biopsy may improve diagnostic accuracy. Diagnostic difficulty was associated with myxoid and round cell neoplasms, infections, and tumors located in the paraspinal region. The limited number of references addressing these issues demonstrated the need for more Level I research in the area of biopsy of soft tissue masses.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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.

[Cytologic diagnosis of soft tissue tumors]

Soft tissue swellings represent common clinical signs of a variety of neoplastic and non-neoplastic lesions. Sarcomas are rarely the cause. Fine needle biopsy as a minimally invasive, economic and accurate method is well suited for the diagnostics of recurrent and metastatic diseases. Cytologic diagnosis of primary soft tissue tumors is also feasible but requires close collaboration with other medical disciplines and incorporation of clinical, radiological and morphologic findings. Clinical data such as age, gender, size and topography are also important parameters. Differentiation of the cells and the properties of the extracellular matrix offer initial indications for the differential diagnosis and are the starting point for immunohistochemical and molecular analyses (FISH, RT-PCR). These analyses can be performed on cytological smears, on paraffin-embedded cell blocks on snap frozen material.

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.