肛管直肠恶性黑色素瘤的临床病理特征分析

目的探讨肛管直肠恶性黑色素瘤（anorectal malignant melanoma,AMM）的临床病理学特征。方法收集南京中医药大学附属南京中医院2008年7月至2019年8月收治的15例AMM患者的临床病理资料，分析其临床及病理组织学特征、免疫表型及BRAF基因突变情况，并复习相关文献进行分析。结果15例AMM患者年龄45～88岁（中位年龄66岁），男5例，女10例。临床主要表现为便血、肛管直肠肿物、肛门坠胀疼痛。15例中仅有2例临床诊断为恶性黑色素瘤。镜下肿瘤细胞形态多样，异型性明显，核大，核仁明显，胞浆内可见黑色素颗粒。免疫组化结果显示肿瘤细胞表达S 100、Vimentin、HMB 45及Melan A，不表达CK、EMA、LCA，Ki 67表达10%～60%阳性不等，1例可见BRAF基因突变。结论AMM是一种临床少见、预后较差的恶性肿瘤，临床表现无特异性，临床误诊率高，明确诊断需结合免疫组化标记物检查。治疗上以手术为主，辅以放疗、化疗及免疫治疗等。

Clinicopathological features of anorectal malignant melanoma

Objective To investigate the clinicopathological features of anorectal malignant melanoma.Methods The clinicopathological datas of 15 cases of AMM were collected,The clinical and histopathological features and immunohistochemical phenotypes were analyzed,the mutations of BRAF gene were investigated and relevant literatures were reviewed.Results Fifteen patients aged 45 to 88 years old(median age 66 years old),the ratio of men to women is 1∶2.The main clinical manifestations were hematochezia,anorectal mass and pain of anal distention.Microscopically,the tumor cells are various in morphology,distinct in heteromorphism,large in nucleus,obvious in nucleolus and melanin granules in cytoplasm.Immunohistochemistry showed that the tumor cells expressed S-100,Vimentin,HMB-45 and Melan-A,but did not express CK,EMA and LCA,and Ki-67 expression varied from 10%to 60%.BRAF gene mutations were found in one case.Conclusions AMM is a rare malignant tumor with poor prognosis.Its clinical manifestations are not characteristic and its misdiagnosis rate is high.The final diagnosis should be combined with immunohistochemical markers.Surgery is the main treatment,supplemented by radiotherapy and chemotherapy,immunotherapy and so on.