新生儿先天性黑色素瘤临床病理观察

Congenital melanoma in neonate:a clinicopathologic analysis

目的探讨先天性黑色素瘤的发生、病理学特点及鉴别诊断。方法对1例新生儿先天性黑色素瘤的临床表现、组织形态学及免疫组化进行分析并复习相关文献。结果患儿男性,出生6h。出生时发现骶尾部红色肿物及腰背部黑色斑块。镜下见形态一致的异型小细胞在真皮内呈片状分布,部分瘤细胞内、外见黑色素颗粒。肿瘤浸润表皮并形成溃疡及坏死。免疫组化：S-100和HMB45（＋）,melanA（-）。结论先天性黑色素瘤可由胎盘转移、巨大的黑色素细胞痣起源和子宫内原发3种途径发生。不同途径起源的肿瘤发生部位和预后有一定区别。确诊主要依靠组织病理学并辅以免疫组化标记。需要与具有黑色素细胞特点的良性病变及癌、恶性淋巴瘤和原始神经外胚层肿瘤鉴别。

Objective To study the clinicopathologic characteristics of congenital melanoma. Methods The clinicopathologic and immunohistochemical findings in a case of congenital melanoma were presented with review of relevant literatures. Results The patient was a 6-hour-old boy. A tumor was found in his sacrococcygeal region when he was born. Histopathologic examination showed that atypical tumor cells were diffusely located in both dermis and subcutaneous fat tissues. In some areas, tumor cells also infiltrated into epidermis, which resulted in ulcers and necroses in epidermis. Those tumor cells were uniform small and round. By immunohistochemical stains, the tumor cells were positive for S- 100 and HMB45, but negative for melan A. Conclusion Congenital melanoma may develop in uterus through one of the following ways： transmission by metastasis through the placenta, arising within a giant congenital melanocytic nevus and primary congenital melanoma arising in utero. Different way means different involved site and prognosis. Definite diagnosis should be based mainly on pathological examination in assistance with immunohistochemical analysis. Differential diagnosis includes bewgn lesions with melanocyte, carcinoma, malignant lymphoma and primary neuroectodennal tumor.