Department of Pathology, Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
Diagn Pathol. 2010 Jun 15;5:36. doi: 10.1186/1746-1596-5-36.
Invasive lobular carcinomas (ILC) of breast typically demonstrate intracytoplasmic mucin. We present a unique case of classical type ILC with abundant extracellular mucin and strong ERBB2 (HER2/neu) expression confirmed by immunohistochemistry and fluorescent in situ hybridization. Dual E-cadherin/p120 immunohistochemical stain demonstrated complete loss of membranous E-cadherin and the presence of diffuse cytoplasmic p120 staining, confirming the lobular phenotype. The tumor cells showed ductal-like cytoplasmic MUC1 staining, but were negative for MUC2 and other mucin gene markers. In addition, studies of tissue microarrays of 80 breast carcinomas with mucinous differentiation revealed 4 pure mucinous carcinomas showing significantly reduced E-cadherin staining without redistribution of p120 into cytoplasm. The findings suggest that the presence of extracellular mucin does not exclude a diagnosis of lobular carcinoma, and the morphologic and molecular characteristics of lobular and ductal carcinomas are more complex than previously appreciated.
乳腺浸润性小叶癌（ILC）通常表现为细胞内粘蛋白。我们报告了一例具有丰富细胞外粘蛋白的经典 I 型 ILC 的独特病例，免疫组织化学和荧光原位杂交证实 ERBB2（HER2/neu）表达阳性。E-钙黏蛋白/p120 双重免疫组化染色显示膜 E-钙黏蛋白完全缺失，细胞质 p120 染色弥漫，证实为小叶表型。肿瘤细胞表现出导管样细胞质 MUC1 染色，但 MUC2 和其他粘蛋白基因标志物均为阴性。此外，对 80 例具有粘液分化的乳腺癌组织微阵列的研究显示，4 例纯粘液癌 E-钙黏蛋白染色明显减少，而 p120 无细胞质重新分布。这些发现表明，细胞外粘蛋白的存在并不能排除小叶癌的诊断，小叶癌和导管癌的形态和分子特征比以前认识到的更为复杂。
