[Clinicopathological factors in risk prediction of lymph node metastasis in papillary thyroid carcinoma]

To explore the relationship between histomorphological factors and lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC).

A total of 153 paraffin-embedded specimens of PTC treated at Beijing Tongren Hospital, Capital Medical University were collected from January 1, 2006 to December 31, 2013 and assessed by hematoxylin and eosin staining. The tumor growth patterns (infiltrative tumor border, lateral tubular growth and intraglandular dissemination), histomorphological characteristics (hobnail features, loss of cohesiveness/polarity (LOCP) and micropapillary structures) and several clinicopathological parameters were evaluated for their values in LNM.

Among them, there were infiltrative tumor border (n = 128), lateral tubular growth (n = 34), intraglandular dissemination (n = 30), extrathyroidal extensions (n = 53), hobnail features (n = 37), LOCP (n = 59) and micropapillary structures (n = 70). According to univariate analysis, patient age < 45 years, tumor size of 10 mm or more, infiltratve tumor border, lateral tubular growth, intraglandular dissemination, hobnail features, LOCP and micropapillary structures predicted LNM for PTC (P < 0.05); whereas gender, multifocality and extrathyroidal extensions did not (P > 0.05). According to multivariated analysis, tumor size of 1 cm or more, infiltratve tumor border, hobnail features, LOCP and micropapillary structures were independent predictive factors of LNM for PTC (P < 0.05). After a median follow-up period of 42 months, 4/82 patients suffered from locoregional recurrence. The estimated 5-year locoregional recurrence was 4.88%. Among 4 logcoregional recurrence cases, 3 involved in lymph nodes and 1 in remaining thyroid. Among 3 lymph node metastasis cases, there were hobnail feature (n = 1), LOCP (n = 1) and LOCP and micropapillary structure (n = 1). None of hobnail feature, LOCP or micropapillary structure was found in recurrent case of remaining thyroid.

Correlated with lymph node metastasis in PTC, hobnail features, LOCP and micropapillary structures may be used as independent predictive factors of LNM so as to improve treatment and follow-up strategies for PTC.