[A comparative study of cytological and histological studies of the thyroid gland].

We compare the results of fine-needle aspiration cytology of the thyroid gland with postoperative histological findings in 533 patients with thyroidectomy operated on between 1987 and 1994. The classification of the cytological preparations followed the proposal of Weiss and Pilz [35] with the groups 0-IV. In group 0 the most frequent findings were cystic changes in multinodular goitre or malpuncture, respectively. The groups I and II contained cases with multinodular goitre, thyroiditis and follicular adenomas, but 4 carcinomas too. The group III comprised particularly follicular adenomas and carcinomas (8 cases). Both cases in group IV were carcinomas. In group III (cytologic group with suspicious findings) there were 65 cases with false positive results of the cytologic investigation resulting in a specificity of 86.4%. 4 out of 14 thyroid carcinomas could not be detected by cytologic preparations corresponding to a sensitivity of 71.4% for carcinomas. The false negative rate for thyroid carcinomas in group II was caused by regression areas in the center of the tumors (3 cases) as well as one microcarcinoma. Preoperative fine-needle aspiration cytology of the thyroid gland reduces the number of patients operated on for multinodular goitre or cold nodules especially in cases suspicious of carcinoma.