Diagnostic accuracy and use of aspiration biopsy in the management of thyroid nodules.

The diagnostic accuracy of fine-needle aspiration biopsy of thyroid nodules was assessed in 111 patients who underwent thyroidectomy and in three persons whose thyroid glands were examined at autopsy. The basis for not performing surgery in 107 patients studied during the same period is also discussed. Carcinoma (excluding incidental occult carcinoma) was found in 76% of the nodules with malignant cytologic findings (class 5, 10/10; and class 4, 3/7), 20% (3/15) of the nodules with suspicious cytologic findings (class 3), and 9% (8/87) of the nodules with benign cytologic findings (classes 1 and 2). The major reasons for avoiding surgery included resolution of the nodule after aspirating a cyst (eight cases) or after hemorrhage (two cases), multinodular goiter (13 cases), functioning nodule (ten cases), lymphocytic thyroiditis (nine cases), high operative risk without suspicious cytologic findings (15 cases), and response to suppression therapy (27 cases). Among 186 patients given thyroxine suppression therapy, 10% of the nodules disappeared and 12% decreased to less than 1 cm in diameter or more than 50% in volume. Aspiration biopsy is useful to select patients for early surgery or for long-term medical management. Its lack of precision, however, requires that it be employed as an adjunct to other clinical considerations.