Fine Needle Aspiration Cytology of Thyroid Nodules: Evaluation of Diagnostic Accuracy

Thyroid Fine-Needle Aspiration in Taiwan: The History and Current Practice

In Taiwan, thyroid cancer is the most common endocrine gland malignancy and the incidence of thyroid cancer has increased four-fold in the past two decades. Fine-needle aspiration is an accurate and cost-effective method of evaluating thyroid nodules and has been the gold-standard diagnostic tool for thyroid tumors in Taiwan since the 1980s. This article reviews the history, current practice, reporting systems, training, and quality assurance for thyroid fine-needle aspiration cytology in Taiwan.

Fine-needle aspiration cytology of thyroid nodules with Hürthle cells: cytomorphologic predictors for neoplasms, improving diagnostic accuracy and overcoming pitfalls

OBJECTIVES

Hürthle cells (HCs) are follicular-derived oncocytic cells seen in a variety of neoplastic and nonneoplastic pathologic entities of the thyroid gland. This study was to report our experience of the surgical outcome on the finding of HCs on fine-needle aspiration biopsies (FNABs) of thyroid nodules, to identify cytologic predictors of HC neoplasms and an attempt to overcome diagnostic pitfalls.

STUDY DESIGN

This was a retrospective study of all FNAB of thyroid nodules with findings of HCs with subsequent surgical resection. The FNAB slides of 70 thyroid nodules were blindly reviewed for specific cytomorphologic characteristics. The cytologic findings were correlated with the corresponding final surgical pathology diagnosis.

RESULTS

The patients ranged in age from 25 to 78 years with a male:female ratio of 1:2. There were 19 false-negative and 4 false-positive cases. Overall high cellularity, scant colloid and >90% HCs on FNAB are consistently seen in a neoplastic HC process. All cases of Hashimoto's thyroiditis were associated with prominent nucleoli and 92% of cases demonstrating transgressing vessels were neoplastic.

CONCLUSION

Diagnostic accuracy can be improved by following the current Bethesda classification system. A constellation of cytomorphologic features in conjunction with clinical findings can be considered a strong predictor of a neoplastic process.