5例肛管直肠恶性黑色素瘤的临床病理分析

本文报告５例原发肛管直肠的恶性黑色素瘤的临床病理及免疫组化特点。在本组病例中女性为主，平均年龄为５８．４岁。２例肿瘤位于肛管部，２例位于齿状线处，ｌ例位于直肠下端。光镜检查４例可见色素颗粒，免疫组化染色：肿瘤细胞对Ｓ－１００蛋白，ＨＭＢ４５及Ｖｉｍｅｎｔｉｎ抗体呈阳性反应。在１例肿瘤旁的鳞状上皮内可见早期浅表黑色素瘤表现，另１例直肠粘膜柱状上皮内可见非典型增生的色素细胞。提示肛管直肠的黑色素瘤既可以来自肛管鳞状上皮内的色素细胞，也可以来自直肠柱状粘膜上皮内的色素细胞。

A clinicopathological analysis of 5 cases with anorectal malignant melanoma

The clinicopathological and immunohistochermcal features of anorectal malignant melanoma in 5 cases were reported. Most of the cases were female and their average age was 58.4 years old. The tumor was located in the anal canal in two cases. at the dentate line in another two and at the lower end of the rectum in one.Under light microscope, pigment granules were seen in 4 cases.Immunohistochemical studies showed that the neoplastic cells reacted positively to anti-S-100 protein, anti-HBM45 and anti-vimentin antibodies. Atypical hyperplastic melanocytes were identified in the rectal columnar epithelium in one case and early superficial melanoma manifestations were seen in the squamous epithelium at the surrounding of the tumor in another case. The results show that the anorectal melanoma may arise from either melanocytes in the anal squamous epithelium or from those in the rectal columnar epithelium.