RESUMO
OBJECTIVE: To determine whether multinucleated giant cells (MGCs) in fine needle aspirates can help differentiate papillary thyroid carcinoma (PTC) from benign nodular goiter (BNG). STUDY DESIGN: Specimens from 100 cases of PTC and 100 cases of BNG with surgical and pathologic proof were randomly retrieved. The morphologic characteristics and frequency distribution of the maximal size and number of MGC nuclei were analyzed. A retrospective review of medical records was also undertaken. RESULTS: MGCs were twice as frequent (40%) in PTC than in BNG (26%) (odds ratio = 1.90). Most MGCs in BNG tended to be smaller and ovoid, with foamy cytoplasm, and had fewer nuclei. No MGC in BNG was > 116 microns in diameter or had > 27 nuclei. In contrast, MGCs in PTC were more diverse in size, shape, cytoplasm and number of nuclei. No significant association was found between the presence or nature of MGCs and disease extent in PTC. CONCLUSION: The presence of large MGCs with dense cytoplasm in a thyroid nodule without clinical evidence of thyroiditis should prompt careful exclusion of associated PTC.