Morphometry in the cytologic evaluation of thyroid follicular lesions

The current study was undertaken to evaluate the quantitative estimation of cytologic features on aspirated smears for the preoperative differential diagnosis of follicular lesions of the thyroid.

The subjects were 60 patients with follicular lesions of the thyroid (including 20 follicular carcinomas, 15 follicular adenomas, and 25 adenomatous goiters) whose histopathologic explorations were conducted fully postoperatively. Using a microscope connected to a computerized video system, the mean nuclear area, the mean nuclear perimeter, the circular rate, the largest to the smallest dimension ratio (LS ratio) of the nuclei, and the coefficient of variation of the nuclear area (NACV) were measured and analyzed.

Among the quantitative morphometric parameters of nuclei, the circular rate was significantly higher in the group with adenomatous goiters than those with follicular carcinomas (P < 0.00001) and adenomas (P < 0.005). The group with follicular carcinomas had a higher LS ratio than the group with adenomatous goiters (P < 0.0005). The NACV value increased as the malignant potential of the lesion increased and showed significant differences between the groups. When a NACV of 21.5% was chosen as the cutoff point, the incidence of malignancy was significantly higher in patients with high NACV values than in those with low NACV values (P < 0.00001). Using this borderline value, it was possible to distinguish malignant from benign diseases with a sensitivity of 85.0%, a specificity of 82.5%, and an accuracy of 83.3%.

Preoperative quantitative estimations of cytologic nuclear features are useful for the preoperative differential diagnosis of follicular lesions of the thyroid.