Fine-needle aspiration cytology in the preoperative diagnosis of thyroid nodules.

Fifty consecutive patients were studied to assess the utility of fine-needle aspiration cytology for the diagnosis of hypofunctioning thyroid nodules. In two patients, cysts were evacuated and did not recur. Thirty-three patients underwent excisional biopsy; the aspiration biopsy result was not a criterion for surgery. Satisfactory aspiration specimens were obtained in 32 patients (97%). The diagnosis in nine aspiration specimens was malignant; of these seven (78%) were correct and there was one false-positive and one occult carcinoma unrelated to the clinically detected nodule. Five aspirations showed suspected malignancy; of these, two were carcinoma, one was an occult carcinoma, and two were benign. Eighteen aspirations were interpreted as benign; of these, 17 (94%) were correct and the one false-negative diagnosis was a well-differentiated follicular carcinoma. The procedure is useful in assessing the need for surgery in high-risk patients and in selecting patients for thyroid-suppression therapy.