The morphometric analysis of cell nuclei from fine needle aspirates of thyroid follicular lesions does not improve the diagnostic accuracy of traditional cytologic examination.

In order to evaluate the usefulness of the morphometric analysis in improving the accuracy of the traditional cytologic examination of follicular thyroid lesions, fine needle aspirates from 17 adenomatous goiters, 19 follicular adenomas and 18 follicular carcinomas were examined. In each case 20-50 follicles, accounting from 100 to 200 thyroid cells, were studied by operators unaware of the histologic diagnosis. Nuclear areas (mean, maximum and minimum area) were derived by means of a semiautomatic system and follicular thyroid lesions were classified into three groups (goiter, adenoma and follicular carcinoma) utilizing cut-off values. The results were then compared to the cytologic diagnosis carried out according to traditional (optic microscopy) criteria. Mean values of nuclear areas showed significant differences among the three groups, but a considerable overlap occurred in the size distribution of cell nuclei. At present, therefore, planimetric measurements of cell nuclei in fine needle aspirates do not improve the accuracy of standard cytologic examination in the differential diagnosis of follicular thyroid lesions.