Diagnostic utility of DNA content flow cytometry in follicular neoplasms of the thyroid.

Preoperative diagnosis of follicular carcinoma of the thyroid remains a clinical challenge. This study determined the DNA content parameters of ploidy and proliferative activity levels from cells of normal thyroid tissue, follicular adenomas, and follicular carcinomas to evaluate if these parameters could be used as an adjunct to fine needle aspiration in their diagnosis. Statistically significant higher proliferative activity levels were found in the carcinoma groups (mean S-phase fraction [SPF] = 5.0%) compared to 2.9% for follicular adenomas and 1.3% for normal thyroid. DNA aneuploidy was identified in 73% of carcinomas and 36% of adenomas. Because of overlap of SPF values between groups, one could not rule out the presence or absence of malignancy based on DNA content parameters alone. These measurements may, however, be an aid to the decision making in patients who are poor surgical risks.