The Diagnostic Value of Ultrasound-Guided Fine Needle Aspiration Cytology in the Thyroid Nodules / 대한내분비학회지

ABSTRACT

Background: Thyroid nodule is a common disease of thymid gland. The incidence of malignant nodule is about 3%, so most of thyroid nodules are benign. Because most thyroid nodule morbidity is related to cancerous lesions, early detection of malignant nodule is important. However, some of these nodules are srnall sized or deep seated which were not detected by physieal exarnination but by ultrasonography incidentally. In these cases the diagnostic approach is difficult with conventional methods but it is easy with ultrasound-guided fine needle aspiration (FNA). However, the role of ultrasound-guided FNA on the thyroid nodules has been poorly evaluated, so we tried to assess the diagnostic value of high resolution ultrasound-guided FNA in the thyroid nodules. Methods: We examined the medical records retrospectively of all patients who were engaged in high resolution ultrasonography(ATL Ultramark-9, 10 MHz linear transducer) due to thyroid nodules and/or other thyroid abnormalities from September, 1995 to March, 1996. Ultrasound- guided FNA was performed in 137 patients with palpable or nonpalpable(small sized or deep seated) nodules which were detected by high resolution ultrasonography. Results: The mean age of the patients was 45 and most of them were middle aged. Male to female ratio was 18.1. Malignant nodules were frequent in patients over 30 yus of age. Of 137 patients 43 were involutional change, 45 hyperplasia, 12 Hashimotos thyroiditis, 12 follicular neoplasm, ll papillary carcinoma, 1 Hurthle cell tumor, 1 medullary carcinoma, and 12 inadequate specimen. In 22 cases thyroid nodules were not detected by physical examinatian but by ultrasonography and in 31 cases additional thyroid nodules were detected by ultrasonography. In the nature of thyroid nodules, 99 cases were solid, 16 cystic, 22 mixed. Malignant nodule were more frequent in the solid nodule, but thete was no significant difference between each group. The size of masses was categorized into four groups. Thirty-one cases measured less than 1cm, 63 between 1cm and 1.9cm, 29 between 2cm to 2.9cm, and 14 over 3cm. The malignant nodule was not palpable in 3 cases and the smallest was 0.7cm in diameter. Most of malignant lesions were between 1cm and 2.9cm, but the difference of incidence rate of rnalignant nodules between each group was not significant. The incidence rate of malignancy was 8.8% in solitary nodule and 8.7% in multiple nodules. Twenty-three cases including 12 malignancies diagnosed by FNA underwent operation. Of those 13 were papillary earcinoma, 1 follicular carcinoma, 1 medullary carcinoma. Upon the correlation of ultrasound-guided FNA cytology with pathologic diagnosis, the sensitivity of ultrasound-guided FNA cytology in differentiating benign and malignant nodule was 80.0%, the specificity 100% and overall diagnostic accuracy was 86.1%. The obtainability of adequate cytologic specimen by ultrasound-guided FNA was 91%. No complication except pain was noted during this study. Conclusion: High resolution ultrasound-guided FNA cytology in the thyroid nodules may be useful in the diagnosis of thyroid cancer especially in the nodules which were small sized or deep seated and also useful in early detection of recurrence of thyroid cancer.