直肠恶性黑素瘤9例临床病理分析

Clinicopathologic analysis of 9 cases of primary anorectal malignant melanoma

目的:探讨直肠恶性黑素瘤(anorectal malignant melanoma,AMM)的临床病理和免疫组织化学特征、鉴别诊断和预后。方法:观察9例AMM的临床病理特点,均进行免疫组织化学染色。结果:9例AMM临床表现为便血、脓血便,大便性状改变。肿瘤呈息肉样3例,隆起型病灶伴溃疡形成4例,溃疡型病灶2例,镜下改变与皮肤黑素瘤相似,细胞学形态可分为上皮样细胞型5例,梭形细胞型1例,小细胞型2例,血管外皮瘤样型1例。免疫表型黑素瘤相关抗原HMB45阳性8例,S-100均阳性,黑素瘤相关抗原/黑素-A抗体(MELAN-A)阳性7例,波形蛋白阳性8例。结论:AMM的临床病理特点及抗原表达与皮肤黑素瘤无明显区别。AMM是一种少见的高度恶性肿瘤,预后差,临床易误诊。HMB45、S-100、MELEAN-A阳性有助于诊断与鉴别诊断。

Objective： To explore the clinicopathological and immunohistoche mical features of primary anorectal malignant melanoma（AMM） as well as its diagnosis and prognosis.Methods： The clinical pathological characteristics of 9 cases of AMM were observed.All the cases were studied by immunohistochemical technique.Results： The clinical manifestations of the 9 cases of AMM were bloody stool,bloody purulent stool,and alteration of bowel habit and bowel trait.Polypoid type tumors were observed in 3 cases,protrude type with ulcer in 4 cases and ulcer type in 2 cases.The histopathological feature of primary melanoma was similar to that of the skin melanoma were classified into epithelioid cell type 5 cases,spindle cell type 1 case,small cell type 2 cases and hemangiopericytoma-like type 1 case.In the immunophenotype melanoma,positive fos-related antigen HMB45 was observed in 8 cases,positive S-100 in 9 cases,positive melanoma-A（MELAN-A） in 7 cases and positive vimentin in 8 cases.No significant difference in the clinicopathogical features and the expression of antigens were observed between the AMM and the skin melanoma.Conclusions： AMM is a rare and highly malignant tumor with poor prognosis and easily misdiagnosed.Detection of HMB45,S-100 and MELAN-A protein may be of help to the diagnosis and differential diagnosis of the tumor.