DNA flow cytometry of thyroid neoplasms.

Mechanically dispersed cell suspensions from 23 thyroid lesions were studied by acridine orange flow cytometry. Eight of 14 carcinomas (three papillary, two medullary, two Hürthle cell, and one follicular) manifested abnormal DNA indices ranging from 0.6 to 2.0. Six carcinomas (four papillary and two medullary) were diploid. Four patients having papillary carcinomas with diploid DNA content were young women whose clinical course of disease was indolent. Three papillary carcinomas with abnormal DNA content were found in older men with clinically aggressive disease. One benign adenomatoid nodule displayed a small population with a low-degree hyperdiploid stemline (DNA index = 1.1) with low proliferative activity. Differentiation between clinically indolent and aggressive carcinomas may be possible by nuclear DNA determination, but further work is needed to determine the importance of proliferative activity in thyroid carcinoma.