DNA aneuploidy as a specific marker of neoplastic cells in FNAB of the thyroid

OBJECTIVE: To investigate whether DNA image cytometry (ICM) could be of val ue in the specific identification of neoplastic cells in cytologic specimen s of the thyroid. STUDY DESIGN: FNABs of thyroid from 162 patients with different benign and neoplastic diseases were investigated, Nuclear DNA content in thyroid cells was measured after Feulgen staining using a TV image analysis systenz. Dat a were correlated with clinical and histologic patient follow-up. The occur rence of abnormal DNA stemlines was used as a marker for aneuploidy and thu s for neoplasia. RESULTS: None of the 89 cases without tumor cells revealed DNA aneuploidy. An abormal DNA stemline was found in 55% of histologically proven benign th yroid tumors (follicular or oncocytic adenomas) and in 59.5% of malignant t umors. The positive predictive value of DNA aneuploidy in FNABs of the thyr oid for neoplasms was 100%. The negative predictive value of DNA nonaneuplo idy for the prediction of tumor-free histologic or clinical follow-up was 7 9.4%. CONCLUSION: DNA image cytometry may be helpful in the specific identificati on of neoplastic follicular cells. DNA ICM on FNABs of the thyroid is an ad ditional tool to achieve early identification of patients with nodular lesi ons of the thyroid that have to be operated on. DNA euploidy excludes the p resence of neither malignancy nor neoplasia.