Significance of Fine-Needle Aspiration Cytology and Frozen Section Biopsy of Thyroid Nodules / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Although fine needle aspiration (FNA) cytology is a safe, simple and relatively accurate procedure, satisfactory samples cannot be obtained in about 10-20% of cases and there is also difficulty in differentiating between benign and malignant lesions in follicular neoplasm. Authors have compared preoperative FNA results and frozen section biopsy with permanent histologic findings and evaluated the significance of FNA cytology and frozen section biopsy in the diagnosis of thyroid nodules. MATERIALS AND METHODS: The medical records of 136 patients who underwent FNA cytology and thyroidectomy from October 1, 1993 to September 30, 1998 at the department of Otolaryngology and General Surgery of Ewha Womans University Mokdong Hospital were retrospectively analyzed. RESULTS: Among the 136 patients who received FNA, there were 75 cases (55.1%) diagnosed as benign, 30(22.1%) as malignant, 13(9.6%) as suspicion of malignant and 18(13.2%) as unsatisfactory. Sensitivity of FNA was 77.1%, the specificity 91.4%, and the accuracy 85.6%. Frozen section biopsy was performed in 118 patients and the sensitivity and specificity rate was 78.3% and 100%, respectively. CONCLUSION: FNA cytology has a high sensitivity (77.1%) and specificity (91.4%) rate. It is therefore a valuable initial procedure for diagnosing thyroid nodules and reducing unnecessary extensive surgery. When FNA yields a diagnosis of follicular neoplasm, frozen section biopsy having a specificity rate of 100% is an important step in determining the extent of operation.