Histomorphological factors in the risk prediction of lymph node metastasis in papillary thyroid carcinoma

Few clinicopathological parameters have been identified as independent predictive factors for lymph node metastasis. This study evaluated the predictive ability of three histological characteristics of PTC in lymph node metastases: hobnail features, loss of cohesiveness/polarity (LOCP) and micropapillary structures.

Tissue specimens from 153 patients with histologically confirmed PTC including 112 cases of papillary thyroid microcarcinoma (PTMC) were enrolled in this study. Three histological characteristics (hobnail features, LOCP and micropapillary structures) and several clinicopathological parameters were evaluated for their value in predicting lymph node metastasis. Hobnail features, LOCP and micropapillary structures were each significantly associated with and found to be independent predictive factors for lymph node metastasis (P < 0.05). These three histological characteristics were closely correlated with one another (P < 0.001). Six of the seven possible combinations of these three histological characteristics were independently correlated with lymph node metastasis (P < 0.05). Among these combinations, the coincidence of all three histological parameters represented the strongest independent predictive factor for lymph node metastasis (OR: 3.270, P = 0.006).

Our study demonstrates that hobnail features, LOCP and micropapillary structures, either alone or in combinations, represent strong independent predictive factors for lymph node metastasis in PTC.