Correlation of Thyroid Cytology with Surgical Histology

Abstract

Objective: 1) To assess the predictive value of thyroid cytology by fine needle aspiration (FNA) at our institution in detecting thyroid malignancy since the introduction of the Bethesda System. 2) To identify other potential predictors of malignancy. Method: Records of patients who underwent thyroid FNA and subsequent surgery at University of Missouri between 2007 and 2012 were reviewed. Data collected included cytologic and pathologic diagnoses as well as potential predictors of malignancy and demographic data, including radiation exposure, radiologic findings of calcification and increased vascularity, age, and gender. Results: A total of 378 cases were eligible for review. Of these, one-third met inclusion criteria. Cytology characterized as malignant or benign were found to have high concordance with surgical pathology findings. The diagnosis atypia of undetermined significance (AUS) and its malignancy risk were observed 2 to 3 times higher than that prescribed by the Bethesda guidelines. The majority of cases with cytologic features of follicular neoplasm were found to be benign. However, a significant number of incidental cases of papillary microcarcinoma were observed within this group. Papillary thyroid carcinoma was identified in 60% of cases with features suspicious for malignancy. Conclusion: While benign and malignant cytologies are highly predictive, there exists wide variation in the interpretation of uncertain categories. Malignancy risk associated with AUS ranges from 6% to 28% in the literature. These results suggest that trends developed from institution-specific data may be more predictive in guiding post-FNA management.