肛管直肠原发恶性黑色素瘤12例

目的研究肛管直肠恶性黑色素瘤的临床病理及其细胞起源。方法肛管直肠原发恶性黑色素瘤手术切除标本１２例，其中２例还于术前作活检。所有病理标本常规切片，ＨＥ染色；１例作Ｆｏｎｔａｎａ染色，１例作Ｓ＿１００染色，瘤旁上皮也作观察。结果全部为女性，平均年龄６２．６岁。肿瘤位置，白线与齿状线之间３例，齿状线６例，肛管直肠线与齿线之间１例，直肠下端２例。光镜下，１０例见到黑色素颗粒；另２例中，１例Ｆｏｎｔａｎａ染色阳性，１例Ｓ＿１００阳性。８个肿瘤的瘤周柱状上皮或／和鳞状上皮内可见异型增生的色素细胞。结论肛管直肠黑色素瘤起源于肛管非皮肤性鳞状上皮内的色素细胞，直肠柱状上皮内的色素细胞，或残余泄殖腔柱状上皮内的色素细胞

Primary malignant melanoma of the anorectum: analysis of 12 cases

AIMS To study the clinicopathological features and the origin of tumor cells of anorectal malignant melanoma. METHODS Tweleve patients of anorectal malignant melanoma were taken during operation and 2 of them were also biopsied before operation. All samples stained by HE, one by Fontana and one by S_100 and the surrounding epithelium were observed. RESULTS All patients were females and their average age was 62.6 years old. The tumors were located between the anococcygeal line and the dentate line in 3 cases, at the dentate line in 6, between the dentate line and anorectal line in one and at the lower end of the rectum in 2. Under light microscope, pigment granules were seen in 10 cases. In others, one case reacted positively by Fontana method and other cases reacted positively to anti_S_100 protein. Atypical hyperplastic melanocytes were identified in columnar or/and squamous epithelium at the surrounding of 8 cases. CONCLUSIONS The anorectal melanoma may arise from either melanocytes in the anal nondermal squamous epithelium or from those in the rectal columnar epithelium. It may also arise from those in columnar epithelium of remnant of cloaca.