目的：探讨多灶甲状腺微小乳头状癌（PTMC）的临床病理特征。方法：回顾性分析2013年5月—2016年4月297例手术治疗并经病理证实的PTMC患者临床资料。结果：297例PTMC患者中，多灶PTMC 70例（23.6%）。与单灶PTMC患者比较，多灶PTMC患者肿瘤直径小（0.54 cm vs. 0.69 cm）、包膜侵犯率高（18.6% vs. 8.8%）、行甲状腺全切比例高（87.1% vs. 41.4%），差异均有统计学意义（均P<0.05）。癌灶数≥3多灶PTMC患者与癌灶数=2的PTMC患者比较，前者合并双侧癌的比例增高（88.2% vs. 44.4%）、中央区淋巴结转移的比例增高（47.1% vs. 22.2%），差异均有统计学意义（均P<0.05）。结论：多灶PTMC的病灶更为微小且更易出现包膜侵犯；多灶PTMC的病灶数越多合并双侧癌和中央区淋巴结转移的风险就越大；多灶PTMC应常规行预防性中央区淋巴结清扫。
Clinical features of multifocal papillary thyroid microcarcinoma
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.