Characteristic tumor growth patterns as novel histomorphologic predictors for lymph node metastasis in papillary thyroid carcinoma.

The aim of this study was to investigate the efficaciousness of histological tumor growth patterns in the prediction of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC). All combinations of infiltrative tumor border, lateral tubular growth, and intraglandular dissemination were assessed for their ability to predict LNM in 229 patients. In addition, we analyzed their predictive value within subgroups based on the tumor size and number of tumor nodules. Each tumor growth pattern was significantly associated with LNM, as 11 of the 12 combinations of these 3 patterns were found to be independently predictive of LNM (P < .05). Similar results were observed in both univariate and multivariate logistic regression analyses of PTCs, grouped according to the tumor size and number of tumor nodules. This study has shown that histological features suggestive of invasive tumor growth, including infiltrative tumor border and lateral tubular growth, may be used as independent predictive factors of LNM in PTC, and can improve treatment and follow-up strategies for PTC.