Abstract
Fine needle aspiration biopsy (FNA) performed for thyroid tumors at Kyoto University Hospital during the past 4 years was evaluated in 37 cases classified as Class III (suspicious) based on the Papanicarau classification. Among the 37 cases, 17 cases (46%) proved to be malignant after surgery. We examined the findings of preoperative examinations such as palpation, ultrasonography, CT scanning, to find out cases which did not need an operation. We found that cases which are soft and have no calcification, and cases which are soft and have clear margins, tend to be benign, but the possibility of malignant tumors, such as follicular carcinomas cannot be ruled out in such cases. We concluded that it is usually better to perform an operation for suspicious (Class III) cases.