Correlation of ultrasonography with fine needle aspiration cytology and final pathological diagnoses in patients with thyroid nodules

The aim of this study was to evaluate the relationship of the combined use of ultrasonography (US) and fine needle aspiration cytology (FNAC) with final pathological results in patients with thyroid nodules. We retrospectively reviewed data from 1,725 patients who had received US examination at our institution between January 2006 and February 2008. Of these patients, 102 (5.9%) had undergone surgical treatment, 90 of whom were also examined by FNAC. The results of FNAC were categorized into 4 groups: malignant, benign, indeterminate and unsatisfactory. We then evaluated the correlations between diagnosis and thyroid US, FNAC, and final pathological results. The age of the 102 patients who received surgery ranged from 13 to 79 years (mean age, 45.5 ± 15.3 years). The female:male ratio was 5.4:1. Seventy-eight patients were diagnosed as having benign lesions (76.5%) and 24 patients as having a malignancy (23.5%), including 20 papillary cancers, 1 anaplastic cancer, 1 medullary cancer and 2 metastatic cancers. Ninety patients received FNAC after US. The positive predictive value for detection of malignancy using FNAC was 94.7% (18/19 cases) and the negative predictive value was 93% (66/71 cases). The sensitivity of the cytological diagnosis was 78.3% (18/23 cases) and the specificity was 98.5% (66/67 cases). The overall positive predictive value for malignancy using both thyroid US and FNAC was 94.7% (18/19 cases) and the negative predictive value, 92.8% (77/83 cases). The sensitivity of the combined investigations was 75% (18/24 cases) and the specificity, 98.7% (77/78 cases). Of the 16 indeterminate cytological cases, 3 were diagnosed as having a malignant lesion (18.7%). In patients with cystic lesions, 4.7% of cases (1/21 cases) were diagnosed as malignant. One patient with a papillary microcarcinoma with neck lymph node metastasis had only a tiny calcified spot in the parenchyma of the thyroid. US with FNAC is useful in the initial evaluation of thyroid nodules. Surgical treatment should be considered for indeterminate cases. It is also important to pay attention to microcalcification in diffuse goiters, especially in patients with neck lymph node enlargement.