Abstract
Fine needle aspiration biopsy (FNA) performed for thyroid tumors at Tenri hospital during the past 6 years was evaluated in 502 nodules all resected by surgery. The cytological diagnosis was classified as positive (class N or V) or suspicious (class III) for malignacy, or negative (class II).
1. Sensitivity and specificity for malignant tumor was 77.7% and 97.4%. Accuracy was 90.9%.
2. 94% of the positive group proved to be malignant and 90% of the negative group proved to be benign by histopathological examination after surgery.
3. FNA should be repeated when the cytological diagnosis is class III.
4. The false negative group consisted mainly of calcified tumor and cystic tumor.
5. The false positive group consisted of atypical adenoma and the adenomatous goiter with papillary change.
