Abstract:Objective: To investigate the clinical features of multifocal papillary thyroid microcarcinoma (PTMC). Methods: The clinical data of 297 patients undergoing surgical treatment and pathologically diagnosed as PTMC from May 2013 to April 2016 were retrospectively analyzed. Results: Among the 297 PTMC patients, 70 cases (23.6%) had multifocal PTMC. In patients with multifocal PTMC compared with those with unifocal PTMC, the tumor size was smaller (0.54 cm vs. 0.69 cm), but the incidence of capsular invasion (18.6% vs. 8.8%) and proportion of cases undergoing total thyroidectomy (87.1% vs. 41.4%) were increased, and all the differences had statistical significance (all P<0.05). In multifocal PTMC patients with ≥3 lesions compared with those with 2 lesions, the proportion of cases with bilateral involvement (88.2% vs. 44.4%) and central lymph node metastasis (47.1% vs. 22.2%) were increased, and both differences had statistical significance (both P<0.05). Conclusion: The lesion of multifocal PTMC is relatively small but prone to capsular invasion. The larger the number of lesions in multifocal PTMC patients, the higher is the risk of bilateral cancer involvement and central lymph node metastasis. Routine prophylactic central lymph node dissection is recommended for multifocal PTMC.