Fine needle aspiration cytologic study of the solitary thyroid nodule. Profile of 308 cases with histologic correlation.

The cytologic features and diagnoses of 308 solitary thyroid nodules subjected to fine needle aspiration (FNA) are presented and correlated with the histopathology. The findings reconfirmed the overall utility of FNA cytology in the differentiation of benign from neoplastic lesions and in the specific diagnosis of most types of thyroid lesions. The difficulty in the diagnosis of follicular carcinoma and in its differentiation from follicular adenoma is highlighted. Of note was the finding of Hürthle-cell populations in several types of lesions, which represents a potential diagnostic problem; this potential difficulty was lessened by sampling two or three areas within a nodule, thus obtaining a more truly representative specimen.