42例肛管直肠恶性黑色素瘤病理及免疫组织化学研究

报告４２例肛管、直肠恶性黑色素瘤，占同期肛管直肠恶性肿瘤的１．１９％。临床表现以大便带血、肛门肿物及肿块突出肛门为特征。９０％以上肿物位于齿状线附近。巨检分三型：蕈伞型，结节型、溃疡型。组织学既像癌又像肉瘤，几种细胞混存而以一种为主，形态观察支持“恶黑”起源于表皮基底层黑色表细胞和闱细胞，免疫标记提示黑色素细胞起源于神经嵴。Ｓ－１００蛋白诊断“恶黑”敏感，但特异性不强，多种抗体联用，能提高诊断的准

Pathological and immunohistochemical study on acorectal melanoma

orty two cases of anorectal melanoma were studied which constituted 1.19% of all the anorectalmalignancies collected in this series. 90%of the tumors located near by the dentate line. Grossly,themasses were nodular,fungiform or ulcerated. Histologically, pleomorphic tumor cells mixed togethergiving a feature somewhat like either carcinomatoid or sarcomatoid,with a predominance of one kind ofthe malignant cells. Histopathologic observation supported the idea that this tumor developed from themelanocytes and nevus cells located at the basal layer of the epithelium. Immunohistochemistry provedthat melanocytes originated from the neural crest.S-100 protein was marker with high sensitivity butthe sepcificity not ideal,so that,varied markers are reeommanded in order to improve the accuracy ofdiagnosis.