Fine-needle aspiration biopsy of cold thyroid nodules.

This study analyzes the results of fine-needle aspiration biopsy (FNAB) of hypofunctioning thyroid nodules performed by one physician. There were 68 patients (age range, 20 to 73 years) with 83 aspirations; 30 were interpreted as positive for neoplasm (adenoma or carcinoma), 43 were negative, and ten (12%) were technically unsatisfactory. Thyroidectomy was performed on 25 patients who had positive aspirates. Subsequent morphologic study showed that 13 patients had carcinomas, ten had adenomas, and two had adenomatoid nodules (false-positive rate of FNAB for neoplasms was 8%). One of three thyroidectomy patients with negative preoperative aspirates had a carcinoma and two had adenomas (estimated minimal false-negative rate of FNAB was 9%). Nineteen patients who underwent thyroidectomies had dynamic radioisotopic thyroid angiography. There was no correlation between the pattern of vascularity and the type of neoplasm. Ultrasound (US) study was performed on 17 patients. Both adenoma and carcinoma can be solid or partially cystic. Although approximately 33% of the nodules initially diagnosed by FNAB as follicular or papillary neoplasms had different interpretations on subsequent examination of thyroidectomy specimens, 93% of the patients selected to be operated on had either adenoma or carcinoma. Thus, in this series, FNAB of cold thyroid nodules gave more useful diagnostic information than nodule size, dynamic radioisotopic scan, or US studies.