Abstract: Objective: To analyze the correlation between macrophage count in fine needle aspirate cytology (FNAC） smear and tumor metastasis in papillary thyroid cancer(PTC) and to explore the value of macrophage count in the diagnosis and the progression of PTC. Methods: A total of 1 392 patients with thyroid nodules (excluding subacute thyroiditis) were enrolled in this study. Number of macrophage was counted in FNAC smear of thyroid nodules, and its clinical value for diagnosing PTC was evaluated. Results: Among these patients, 1 253 cases were confirmed as PTC and 139 cases as benign lesion by pathological examination. The positive rates of macrophages in benign and PTC groups were 2.2% and 58.6%, respectively, and was significantly higher in PTC group than in benign group (P<0.05). Of the 1 253 malignant cases, 505 cases had cervical lymph node metastasis and the other had no metastasis. It was denfinted as positive presence when macrophage was found in smears. The positive rates of macrophages in non-metastasis group and metastasis group were 55.2% and 63.6% (P<0.05). When the 1 253 malignant cases were divided into 6 levels by the macrophage count: grade 0 to grade V, the rates of cervical lymph node metastasis in these six grades were 35.5%, 41.6%, 40.3%, 47.8%, 54.5% and 56.5%, respectively, increased with the increase of macrophage count. Conclusions: For thyroid fine needle aspiration cytology examination, the macrophage count may help the diagnosis PTC, and the number of macrophage may reflect the rate of cervical lymph node metastasis of PTC.

Key words: Papillary thyroid carcinoma, macrophages, Tumor-associated macrophages, Lymph node metastasis