10例肛管直肠恶性黑色素瘤临床病理免疫组化研究

Clinical pathology and immunohistochemistry study in 10 cases of anorectal malignant melanoma

目的研究肛管直肠恶性黑色素瘤(简称恶黑)的临床病理特点及免疫组化染色在恶黑诊断中的作用。方法对肛管直肠恶黑的临床资料进行回顾性分析,用免疫组化S-P法作HMB45、S-100、Vimetin等染色。结果10例肛管直肠恶黑临床初步诊断恶黑1例,误诊其它疾病9例。病理形态:上皮样细胞为主7例,梭形细胞为主2例,小细胞似淋巴细胞样细胞为主1例。免疫组化染色:10例HMB-45、S-100均阳性,9例Vimetin阳性,其中1例CK阳性,LCA阴性。结论肛管直肠恶黑临床表现大便带鲜血,无明显黏液,肛门异物及息肉样突出肛门为特征,临床极易误诊。形态观察支持恶黑起源于表皮基底层黑色素细胞,免疫标记提示黑色素细胞起源于神经嵴。HMB45、S-100、Vimetin,三者联合应用能提高恶黑病理诊断的准确性。

Objective To study elinlcopathologieal feature of anorectal malignant melanoma and the role of immunohistochemical stain in diagnosis. Method 10 cases of anorectal malignant malanoma were stud- ied. Expression of HMB45, S - 100, Vimetin were detected by immunohistochemistry with S - P method. Result 1 case is malignant melanoma. 9 cases were misdiagnosed as other diseases. Clinicopathologic features：7 cases with essential epitheliod cell,2 cases with mainly spindle cell, 1 case with small lymphocyte -hke cell. All 10cases of anorectal malignant melanoma were positive to HMB45, S - 100 and 9 cases were positive to vimetin and 1 case were positive to CK,but negative to LCA. Conclusion The faeces with fresh blood,no evident mu- cus. The masses were nodnlar, fungiform or ulcerative. Histopathologic observation supported the idea that this tumor developed from the melanocytes. 10 cases at the basal. - layer of the epithelium. Immunohistochemistry proved that melanocytes originated from the neural crest. Immunohistochemical stain HMB45, Vimetin S - 100 were helpful for diagnosis of malignant melanoma.