目的：探讨多灶性甲状腺微小乳头状癌（PTMC）临床病理特征及预防性中央区淋巴结清扫的意义。方法：回顾湘雅医院甲状腺外科2013年7月—2016年12月收治的270例PTMC患者资料，比较多灶PTMC与单灶性PTMC患者临床病理因素的差异，并分析多灶性PTMC中央区淋巴结转移的危险因素。结果：270例患者中共120例多灶性PTMC（44.4%）。与单灶性PTMC患者比较，多灶性PTMC患者男性比例增加、中央区淋巴结转移与包膜侵犯发生率明显升高（均P<0.05）。多灶PTMC患者的肿瘤最大直径（5~10 mm vs. <5 mm）及是否存在包膜侵犯与中央区淋巴结转移发生率有关（均P<0.05），而病灶的数目（2 vs. ≥3）及分布（单侧vs.双侧）与中央区淋巴结的转移发生率无关（均P>0.05）。结论：多灶性PTMC较单灶PTMC具有较差的临床病理特征，中央区淋巴结转移风险增加。多灶性PTMC行预防性中央区淋巴结清扫是很有必要的，尤其对于是肿瘤较大、有包膜侵犯的患者。
Clinicopathologic features of multifocal papillary thyroid microcarcinoma and significance of prophylactic central neck dissection
Objective: To investigate the clinicopathologic features of multifocal papillary thyroid microcarcinoma (PTMC) and the significance of prophylactic central neck dissection. Methods: The clinical data of 270 PTMC patients treated in the Department of Thyroid Surgery, Xiangya Hospital from July 2013 to December 2016 were reviewed. The differences in clinicopathologic factors between patients with multifocal PTMC and unifocal PTMC were compared, and the risk factors for central lymph node metastasis of multifocal PTMC were determined. Results: Among the 270 PTMC patients, multifocal PTMC was found in 120 cases (44.4%). In patients with multifocal PTMC, the proportion of male cases and the incidences of central lymph node metastasis and capsular invasion were significantly increased compared with patients with unifocal PTMC (both P<0.05). In multifocal PTMC patients, the maximum tumor diameter (5–10 mm vs.<5 mm), and the presence or absence of capsular invasion had significant impact on incidence of central lymph node metastasis (both P<0.05), while the lesion number (2 vs. ≥3) and distribution (unilateral lesion vs. bilateral lesion) showed no significant influence on incidence of central lymph nodes metastasis (both P>0.05). Conclusion: Compared to unifocal PTMC, multifocal PTMC has relatively poor clinicopathologic features and an increased risk of central lymph node metastasis. Prophylactic central lymph node dissection is necessary for multifocal PTMC patients, especially for those who have relatively large tumors and tumors with capsular invasion.