Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Breast J. 2010 Sep-Oct;16 Suppl 1:S10-4. doi: 10.1111/j.1524-4741.2010.00994.x.
Lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia are rare lesions, found incidentally in breast biopsies. They have been regarded traditionally as high-risk lesions, but recent genetic evidence and follow-up data indicates that they also constitute nonobligate precursors of invasive carcinoma. In addition to 16q deletion, a genetic alteration common across the spectrum of low-grade mammary epithelial neoplasia, lobular lesions consistently demonstrate deletion or functional inactivation of the CDH1/E-cadherin gene, with consequent loss of membranous immunoreactivity for the same antigen. The use of E-cadherin in the evaluation of solid mammary carcinoma in situ with ambiguous morphology has identified variants of LCIS characterized by massive acinar expansion and necrosis with calcifications, and/or marked nuclear pleomorphism or signet ring cell formation. In contrast to classic LCIS, these rare lesions are detected mammographically and often occur in association with invasive carcinoma. Genetic analysis of these tumors has confirmed lobular lineage and demonstrated more extensive chromosomal alterations than in classic LCIS. A pleomorphic variant of invasive lobular carcinoma has also been described. Here, we summarize our evolving knowledge of in situ and invasive lobular neoplasia and highlight the implications for patient management.
乳腺原位癌（LCIS）和不典型小叶增生是罕见的病变，在乳腺活检中偶然发现。它们传统上被认为是高风险病变，但最近的遗传证据和随访数据表明，它们也是浸润性癌的非必需前体。除了 16q 缺失（低级别乳腺上皮肿瘤谱中常见的遗传改变）外，小叶病变还始终表现出 CDH1/E-钙粘蛋白基因的缺失或功能失活，从而导致相同抗原的膜免疫反应丧失。E-钙粘蛋白在形态学不确定的实体性乳腺原位癌的评估中的应用，鉴定出了具有大量腺泡扩张和坏死伴钙化、或显著核多形性或印戒细胞形成的 LCIS 变体。与经典 LCIS 不同，这些罕见病变在乳房 X 线照相术中检测到，并且常与浸润性癌相关。对这些肿瘤的遗传分析证实了小叶谱系，并显示出比经典 LCIS 更广泛的染色体改变。也描述了一种多形性浸润性小叶癌变体。在这里，我们总结了我们对原位和浸润性小叶肿瘤的不断发展的认识，并强调了对患者管理的影响。
