OBJECTIVE DIFFERENTIAL CLASSIFICATION OF THYROID LESIONS BY NUCLEAR QUANTITATIVE ASSESSMENT

Quantitative nuclear parameters estimated by morphometric and stereolo gical methods in combination with discriminant analysis were used in o rder to evaluate the diagnostic efficiency of thyroid lesions. This st udy includes 55 patients with thyroid pathology. Samples of follicular adenomas, follicular carcinomas, and papillary carcinomas were examin ed by image analysis to obtain size and form nuclear parameters. Stepw ise discriminant analyses were performed. There was an increase in nuc lear size from follicular adenomas to follicular carcinomas, and a gre ater increase from follicular carcinomas to papillary carcinomas. The increase was more significant when the three-dimensional estimates of the volume-weighted mean nuclear volume were assessed. No significant differences between follicular adenomas and follicular carcinomas were found with respect to the nuclear form factors; however, a significan t increase in nuclear elongation and irregularity was registered betwe en follicular and papillary tumors (p<0.01). The overall accuracy rate of discrimination was 75% when the three lesions were included in the analysis, with an efficiency of 85% for papillary carcinoma samples. These percentages increased when two lesion discrimination was perform ed. The worst discrimination (69% of efficiency) was found between fol licular adenomas and follicular carcinomas.