Solitary thyroid nodules for surgery--the role of fine-needle aspiration biopsy cytology.

The diagnostic accuracy of fine needle aspiration biopsy cytology (FNAC) was assessed in 46 patients, all of whom had histological verification. In the group of patients with microscopic foci of carcinomas excluded, diagnostic sensitivity was 75% and specificity 100%. No false positives were recorded, the false negative rate was 5.0% and the overall accuracy, 95%. Although 6 of the 10 carcinomas were correctly diagnosed by cytology, the correct morphological type of tumor was only identified in three of them. Using clinical suspicion of malignancy alone as a criterion for surgery, 13% of patients would have required surgery with 50% of malignancies still remaining undetected. However using FNAC, clinical suspicion and patients above 50 years of age as combined criteria, 40% of patients would have been subjected to surgery with a resulting yield of malignancy of 100%. These promising results from a initial experience with FNAC confirm its usefulness in the appropriate selection of patients for surgery.