[Preoperative cytodiagnosis by needle aspiration of follicular thyroid lesions].

In the period 1989-92, 2729 F.N.A.B. were performed: 585 with an histological control were reviewed. The aim of the study was to evaluate the risk of carcinomatous occurrence in the follicular-structured smears and to suggest a new cytodiagnostic classification. Out of 398 follicular-structured smears, 188 were colloid nodules (CN), 38 thyreocytic hyperplasias without nuclear atypia (THWNA), 146 predominantly follicular lesions (PFL), 26 follicular lesions with nuclear pleomorphism (FLWNP). The last one showed a high incidence of neoplasia (69.2%) and carcinoma (46.1%); the second and the third only a difference in the incidence of benign neoplasms (32.9 vs. 15.8%), with almost the same percentage of occurrence of malignancies (2.6 vs. 2.1%). Such results suggest that a six-months dilatory strategy might be useful in simple follicular lesions (THWNA and PFL) whereas a cytological follicular pattern with nuclear pleomorphism requires a surgical treatment for the high risk of carcinomatous occurrence.