Department of Pathology, Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Am J Clin Pathol. 2011 Jul;136(1):88-97. doi: 10.1309/AJCP7URIW0QETTAT.
The majority of invasive lobular carcinomas (ILCs) express estrogen receptor (ER) and progesterone receptor (PR) but lack ERBB2 (HER2) amplification. HER2 overexpression is traditionally considered to occur in the pleomorphic variant of ILCs. We describe 12 cases of classical-type ILCs with HER2 overexpression in a 3-year period. All tumors displayed the characteristic morphologic features of classical ILC with uniform cells and discohesive growth patterns. The lobular phenotype was confirmed by the absence of E-cadherin staining. Multiple variables regarding clinical, histologic, and hormone receptor characteristics of tumors were evaluated and compared with a set of HER2- classical ILCs. The study identified 2 main pathologic features associated with HER2 overexpression in classical type ILC: histiocytoid morphologic features and absence of PR expression. ER is still expressed in HER2+ classical ILCs, although the level of expression is significantly reduced compared with the HER2- cases. The implications of the findings are discussed.
大多数浸润性小叶癌（ILC）表达雌激素受体（ER）和孕激素受体（PR），但缺乏 ERBB2（HER2）扩增。HER2 过表达传统上被认为发生在 ILC 的多形性变体中。我们描述了在 3 年内出现 HER2 过表达的 12 例经典型 ILC。所有肿瘤均表现出具有均匀细胞和离散生长模式的经典 ILC 的特征形态特征。通过缺乏 E-钙黏蛋白染色来确认小叶表型。评估了与肿瘤的临床、组织学和激素受体特征有关的多个变量，并与一组 HER2-经典 ILC 进行了比较。研究确定了与经典型 ILC 中 HER2 过表达相关的 2 个主要病理特征：组织细胞样形态特征和 PR 表达缺失。虽然与 HER2-病例相比，HER2+经典 ILC 中 ER 的表达水平显著降低，但仍有表达。讨论了这些发现的意义。
