Abstract: Abstract: Objective　To investigate the clinicopathological significance of histological subtypes in papillary thyroid microcarcinoma (PTMC) and its correlation with cervical lymph node metastasis. Methods　The clinicopathological features of 1 247 patients with PTMC who underwent surgical resection were retrospectively reviewed, and the correlation between histological subtypes of PTMC and cervical lymph node metastasis was analyzed. Results　There were significant differences in gender, age, tumor size, Hashimoto thyroiditis, tumor multifocality, extrathyroidal extension and cervical lymph node metastasis of patients with PTMC between different histological subtypes (P＜0.01). The cervical lymph node metastasis rate in PTMC was 41.2%. And the cervical metastasis rate was high-grade subtype (62.64%) > classic papillary type (42.82%) > follicular type (30.40%) > low-grade subtype (8.33%), with significant differences between the groups (P＜0.01). Logistic analysis showed that male, age under 45 years, tumor size ≥ 5 mm, tumor multifocality and high-grade histological subtypes were independent risk factors for cervical lymph node metastasis (all P＜ 0.05), while follicular subtypes were independent protective factors for lymph node metastasis in PTMC (P＜0.05). Conclusion　The histological subtypes of PTMC are closely related to the high-risk pathological features and cervical lymph node metastasis. Further evaluation of histological subtypes is helpful for clinical treatment strategy.

Key words: thyroid neoplasms, carcinoma, papillary, lymphatic metastasis, papillary thyroid microcarcinoma, histological subtype, clinicopathological parameters