乳腺转移性无色素性上皮样黑色素瘤6例临床病理及分子遗传学特征

Clinicopathological and molecular genetic characteristics of metastatic amelanotic epithelioid malignant melanoma of the breast:a report of six cases

目的探讨乳腺转移性黑色素瘤(malignant melanoma,MM)的临床病理学特征、诊断、鉴别诊断。方法收集6例乳腺无色素性上皮样转移性MM的临床资料,采用免疫组化EnVision两步法检测CKpan、HMB-45、S-100、MART-1、SMA、GCDFP-15、Mammaglobin、GATA-3、TRPS1、CK(AE1/AE3)、TTF-1、CDX2、PR及Ki-67等的表达,FISH法检测基因有无扩增,并分析MM的临床病理学特征。结果肿瘤细胞形态多样,可见组织学类似伴粉刺样坏死的高核级导管原位癌的实性结构,或模糊的乳头状结构,或间质富于淋巴细胞浸润特征。免疫表型:HMB-45、S-100、MART-1均阳性,1例乳腺源性特异性标志物Mammaglobin呈罕见阳性。FISH检测3例发生RREB1扩增,2例为RREB1扩增合并MYB缺失,1例为CCND1扩增合并CDKN2A缺失。结论乳腺转移性无色素性上皮样MM与原发性乳腺肿瘤组织学有重叠性,在乳腺肿瘤鉴别诊断中需考虑其可能性,尤其是三阴型乳腺癌。

Purpose To investigate the clinicopathological features of metastatic malignant melanoma(MM)of the breast in order to improve its understanding.Methods The clinical data of 6 cases of breast achromatic epithelioid metastatic MM were collected.The expression of CKpan,HMB-45,S-100,MART-1,SMA,GCDFP-15,Mammaglobin,GATA-3,TRPS1,CK(AE1/AE3),TTF-1,CDX2,PR and Ki-67 was detected by immunohistochemistry EnVision two-step method.The gene expansion was detected by FISH.Results Tumor cell morphology was diversified,solid nests histologically similar to high-nuclear-grade ductal carcinoma in situ and comedo-like necrosis were observed,and blurred papillary structure or a stroma rich in lymphocytic infiltrate noted.HMB-45,S-100,and MART-1 were all positive,and one case of the breast-derived specific marker mammaglobin showed a rare positive expression.FISH detected three patients who had RREB1 amplification,two patients had RREB1 amplification combined with MYB deletion,and one patient had CCND1 amplification with CDKN2A deletion.Conclusion Breast epithelioid amelanotic malignant MM is historphologically overlapping with primary breast tumors,and its possibility needs to be fully considered in the differential diagnosis of breast tumors,especially in triple-negative breast cancer.