不典型肛管直肠恶性黑色素瘤诊断并文献复习

2016-08-26李鹏钟进刘筠

国际医学放射学杂志 2016年2期

关键词：信号

李鹏　钟进　刘筠

临床探究与评析

不典型肛管直肠恶性黑色素瘤诊断并文献复习

李鹏钟进刘筠

目的探讨不典型肛管直肠恶性黑色素瘤的MRI表现、病理特征及鉴别诊断。方法回顾性分析1例经手术病理证实的肛管直肠恶性黑色素瘤病人的MRI表现及病理资料，并复习相关文献。结果MRI显示肛管直肠交界区一T1等信号、T2稍高信号影，较为均质，呈椭圆形，大小约3.3 cm×4.2 cm×4.3 cm，直肠系膜及系膜筋膜外亦可见多发结节及肿物，大者3.2 cm×2.5 cm×3.8 cm。术中观察显示肿物呈实性，边界清，表面光滑。病理诊断：恶性黑色素瘤。免疫组化显示HMB45（+）、Melan-A（+），提示恶性黑色素瘤。结论不典型肛管直肠恶性黑色素瘤罕见，临床及影像表现通常无特异性，确切诊断需依靠病理学与免疫组织化学检查。

黑色素瘤；肛直区；磁共振成像

DOI：10.19300/j.2016.L4232

【Abstract】ObjectiveTo evaluate the MR findings and pathological features，differential diagnosis of atypical anorectal malignant melanoma.MethodsA case of anorectal malignant melanoma proved by histology was retrospectively analysed，and related literatures were reviewed.ResultsMRI scan revealed a round-like solid mass in the anorectal junction area which showed slightly long T1and long T2signal intensity，well-defined and relatively homogenous.The size of the mass was about 3.3 cm×4.2 cm×4.3 cm.Some nodules and masses were found in the mesorectal area and outside fascia，and the largest one was about 3.2 cm×2.5 cm×3.8 cm.Intraoperative observation showed that the tumor was solid，the boundary was clear，and the surface was smooth.Pathological diagnosis：malignant melanoma tumor.Immunohistochemistry showed HMB45 and Melan-A were positive，suggesting melanoma tumor.ConclusionAnorectal malignant melanoma is rare and usually does not have specific clinical and imaging manifestation.Accurate diagnosis depends on the pathological and immunohistochemical examination.

【Key words】Melanoma；Anorectal junction；Magnetic resonance imaging

Int J Med Radiol，2016，39（2）：175-178

恶性黑色素瘤最常见于皮肤，其次为黏膜组织，如直肠、肛管、外阴和鼻咽部等。一般发生于肛管直肠的黑色素瘤大多数是转移性病变，原发于肛管直肠的黑色素瘤比较少见，通常需要排除其他部位的原发病灶后方可诊断。最终诊断依靠HMB45、Melan-A、Vimentin等免疫组织化学蛋白检测结果判定。肛管直肠区典型黑色素瘤的MRI信号表现有一定特征：即T1WI上为高信号，T2WI上为低信号；不典型恶性黑色素瘤的临床及影像表现均无特异性。本文就1例发生于肛管直肠交界区的恶性黑色素瘤做简要分析并对相关文献进行回顾总结。