[Clinicopathologic Examination of the Resected Cases of Thyroid Benign Tumor Diagnosed Class Ⅲ by Fine Needle Aspiration Cytology].

We describe 13 resected cases of thyroid benign tumor diagnosed as Class Ⅲ by Fine Needle Aspiration Cytology(FNA). The cytological report of these 13 were highly nuclear atypia, papillary cell clumps, nuclear inclusion bodies. Preoperative diagnoses were suspicion of malignant tumors(5 cases)and suspicion of benign tumors(8 cases). Results of the intraoperative frozen section diagnosis were suspicion of malignant tumor(5 cases)and suspicion of benign tumor(7 cases). The operative methods were subtotal thyroidectomy in 5 cases, hemithyroidectomy in 3 cases, lobectomy of the thyroid in 5 cases, the lymph nodes sampling was added in 5 cases. The final pathological diagnoses were follicular adenoma(5 cases), adenomatous goiter(8 cases), In the 5 to 10% of the FNA Class Ⅲ, definitive diagnosis cannot be made even with diagnostic imaging. The FNA Class Ⅲ cases should be treated surgically as a malignant tumor. But the operation method should be selected cautiously in having possibilities to be a benign tumor.