[A clinical pathological study of thyroid nodules detected by physical examinations].

OBJECTIVE: To investigate the relation among the results of thyroid fine needle aspiration cytology (FNAC), thyroid ultrasonography (US) and histopathologic diagnosis about the thyroid nodules detected by physical examination, meanwhile to analyze the etiopathogenesis of the nodules and to evaluate the risk of thyroid cancer and the clinical diagnostic value of FNAC. METHODS: The data of thyroid FNAC results of the thyroid nodules detected by physical examination in 271 cases were analyzed and compared with thyroid US and histopathologic diagnosis. RESULT: (1) The FNAC results showed that the incidences of malignant and suspected malignant lesions were 1.48% and 5.90% respectively. The rate of benign lesions was 78.60% and that of goiter was 29.15%, Hashimoto's thyroiditis 26.57% and thyroid adenoma 15.13%. Benign lesions were more common than malignant ones. (2) Comparison of the FNAC and US results of the thyroid nodules showed that of 96 cases with single nodule the rates of malignancy and suspected malignancy were 3.12% and 7.29%, but of 137 cases with multiple nodules the rates of the two lesions were 0.73% and 6.57%. In 108 cases with smaller nodules (< or = 1.5 cm) the rate of malignancy and suspected malignancy found with FNAC were 0.93% and 7.41%, while in 125 cases with greater nodules (> 1.5 cm) the rate of the two lesions were 2.40% and 6.42%. In 99 solid nodules the rates of malignancy and suspected malignancy were 2.02% and 12.12%, while in 85 cystic or mixed nodules the rates of the two lesions were 2.35% and 2.35%. In the above-mentioned three groups, only the suspected malignancy rate in solid nodules was higher than these in cystic or mixed ones with significant difference (P = 0.013). (3) As compared with the cytological and histological diagnoses in 24 cases, the diagnostic accuracy of FNAC was 75.00% and the rates of false positive and false negative were 25.00% and 0, respectively. CONCLUSIONS: The common causes of the thyroid nodules detected in physical examination are goiter, Hashimoto's thyroiditis and thyroid adenoma. FNAC is a reliable method to define the benign or malignant nature of thyroid nodules with a high diagnostic accuracy. US features of the nodule alone, no matter it is single, solid or of greater size do not sufficiently increase the incidence of thyroid carcinoma.