探讨结肠髓样癌（MC）临床特点、病理免疫组化特征、治疗及预后。

回顾性收集浙江大学医学院附属第二医院大肠外科2019年3月至2022年3月共计9例结肠MC患者临床资料，并结合文献复习分析其临床病理特征及分子病理特征。

9例患者中男性5例，女性4例；年龄30~84岁，右半结肠占比89%，7例病例为Ⅰ~Ⅱ期，2例Ⅲ期。术后病理组织学类型表现为异型肿瘤细胞片状、条索状浸润，细胞边界不清，细胞胞浆丰富嗜酸性，核空泡状，核仁明显，间质及部分肿瘤细胞内多量淋巴细胞浸润。免疫组化结果显示：8例表现为MLH1和PMS2缺失，CD20、CDX2及P53大部分表现为阴性，与常见腺癌不同。术后随访均无复发。

MC是一种少见的结肠低分化或未分化肿瘤，其临床表现、免疫组化特征明显与常见腺癌不同，但预后相对较好。

To investigate the clinical and immunohistochemical features, treatment and prognosis of medullary carcinoma of colon (MC) .

The clinical data of 9 patients with colonic MC from March 2019 to March 2022 were collected retrospectively, the clinicopathologic and molecular pathological features were analyzed with literature review.

Of the 9 patients, five were male and 4 were female, aged 30~84 years, 89% of them were in the right colon, seven cases were in Stage Ⅰ~Ⅱ, two cases were in Stage Ⅲ. The histopathologic features of the tumor were patchy and streaked infiltration of atypical cells, unclear cell boundaries, eosinophilic cytoplasm, vacuolated nuclei and prominent nucleoli, multiple lymphocyte infiltrates into the stroma and some of the tumor cells. The results of immunohistochemistry showed that MLH1 and PMS2 were absent in 8 cases, while CD20, CDX2 and P53 were mostly negative, which were different from common adenocarcinoma. No recurrence was found in the postoperative follow-up.

Medullary carcinoma of the colon is a rare poorly differentiated or undifferentiated tumor of the colon. Its clinical manifestation and immunohistochemical features are obviously different from those of common adenocarcinoma, but the prognosis is relatively good.