Abstract: Objective To predict the occurrence of lateral lymph node metastasis(LLNM)in papillary thyroid carcinoma(PTC)larger than 10 mm in diameter(non-T1A stage)and analyze the metastatic pattern. Methods A retrospective analysis was conducted on 166 PTC patients with the foci diameters larger than 10 mm who underwent thyroidectomy combined with lateral lymph node dissection. Clinicopathological characteristics were evaluated, and the occurrence and pattern of LLNM were analyzed. Univariate and multivariate Logistic regression analyses were used to assess the factors associated with LLNM. A nomogram model was established based on the results, and the receiver operating characteristic(ROC)curve was utilized to evaluate the models accuracy. Results LLNM was most commonly observed in area-Ⅲ(38.1%), and the two-segment metastasis pattern was the most prevalent(42.2%). There was no significant difference in the pattern of LLNM when the lesions were located in different areas of the gland(P>0.05). Multivariate Logistic regression analysis revealed that the location of the lesion, levels of free triiodothyronine(FT3), thyroid-stimulating hormone(TSH), thyroid peroxidase antibodies(TPOAB), and the number of central lymph node metastasis(CLNM)were independent risk factors for LLNM. The area under the curve of the nomogram prediction model is 0.851, indicating a high level of diagnostic accuracy for the established model. Conclusion The nomogram model, incorporating clinicopathological and ultrasonic characteristics, and laboratory results(the number of CLNMs, location of the lesion, FT3, TSH, TPOAB levels), proves to be effective in predicting LLNM in PTCs larger than 10 mm and holds promise for clinical application.

Key words: Papillary thyroid carcinoma, Lateral lymph node metastasis, Central lymph node metastasis, Thyroid stimulating hormone, Thyroid peroxidase antibody, Free triiodothyronine