Department of Pathology, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx, NY, USA.
Montefiore Medical Center and The Eastchester Center for Cancer Care, Bronx, NY, USA.
Histopathology. 2018 May;72(6):965-973. doi: 10.1111/his.13451. Epub 2018 Feb 14.
Neoadjuvant chemotherapy (NAC) is often used to treat localised invasive breast cancer. Invasive mucinous carcinoma (IMC) is considered to be an indolent form of invasive breast cancer, and is rarely treated with NAC. We report the largest series of IMCs treated with NAC, and report a characteristic, but not well recognised, pattern of pathological response.
Our series included seven patients with IMC treated with NAC. Three patients presented with locally advanced disease, three patients had tumours that were HER-2/neu-positive, and four patients had tumours with admixed mucinous and micropapillary features. Clinical and imaging assessment of response showed persistent and, in some cases, progressive disease, despite evidence of significant pathological response in these cases. Pathological assessment after NAC demonstrated marked reduction in tumour cellularity, but persistent space-occupying mucin pools, showing acellular mucin in one case, <1% tumour cellularity in three cases, and 5-10% cellularity in three cases in both the treated breast and axillary lymph nodes.
Persistent mass-forming low-cellular or acellular mucin pools can result in discordant clinical, imaging and pathological findings in IMC treated with NAC.
新辅助化疗（NAC）常用于治疗局部浸润性乳腺癌。浸润性黏液癌（IMC）被认为是一种惰性浸润性乳腺癌，很少用 NAC 治疗。我们报告了最大系列的接受 NAC 治疗的 IMC，并报告了一种特征性但尚未被充分认识的病理反应模式。
我们的系列包括 7 例接受 NAC 治疗的 IMC 患者。3 例患者表现为局部晚期疾病，3 例患者 HER-2/neu 阳性，4 例患者肿瘤具有混合黏液和微乳头状特征。尽管这些病例存在明显的病理反应，但临床和影像学评估显示疾病持续存在，在某些情况下甚至进展。NAC 后的病理评估显示肿瘤细胞减少，但仍存在占位性黏液池，1 例为无细胞黏液，3 例为<1%的肿瘤细胞，3 例为 5-10%的肿瘤细胞，包括治疗过的乳房和腋窝淋巴结。
在接受 NAC 治疗的 IMC 中，持续存在的Mass-forming 低细胞或无细胞黏液池可能导致临床、影像学和病理发现不一致。
