Okubo Takako, Minari Yoshimitsu, Ikura Yoshihiro
Pathology, Takatsuki General Hospital, Takatsuki, JPN.
Breast Surgery, Takatsuki General Hospital, Takatsuki, JPN.
Cureus. 2023 Aug 20;15(8):e43816. doi: 10.7759/cureus.43816. eCollection 2023 Aug.
We present a case study of breast cancer initially diagnosed as invasive ductal carcinoma (IDC), which subsequently substituted into invasive lobular carcinoma (ILC) following neoadjuvant chemotherapy (NAC). A 61-year-old woman presented with a palpable breast lump, and histological examination through core needle biopsy (CNB) confirmed the presence of IDC. After a 6-month course of NAC, the patient achieved a clinically complete response (cCR) and underwent mastectomy. The surgical specimen showed no detectable tumor upon palpation, but microscopic analysis revealed a highly infiltrative growth of poorly-cohesive small atypical cells in the original tumor area. Immunohistochemical staining demonstrated that the tumor cells were negative for E-cadherin, leading to a diagnosis of ILC. To address the histological discrepancy before and after NAC, we re-evaluated the initial CNB using E-cadherin immunohistochemistry. While most tumor cells were E-cadherin positive, a small area displaying scirrhous subtype-like morphology exhibited E-cadherin negativity. Consequently, we revised the diagnosis to mixed IDC-ILC. The differential chemosensitivity between IDC and ILC may provide insight into this phenomenon.
我们展示了一个乳腺癌的病例研究，该病例最初被诊断为浸润性导管癌（IDC），在新辅助化疗（NAC）后转变为浸润性小叶癌（ILC）。一名61岁女性因可触及的乳腺肿块就诊，经粗针穿刺活检（CNB）进行组织学检查确诊为IDC。经过6个月的NAC疗程后，患者达到临床完全缓解（cCR）并接受了乳房切除术。手术标本触诊未发现可检测到的肿瘤，但显微镜分析显示在原肿瘤区域有低黏附性小异型细胞的高度浸润性生长。免疫组织化学染色显示肿瘤细胞E-钙黏蛋白阴性，从而诊断为ILC。为了解决NAC前后的组织学差异，我们使用E-钙黏蛋白免疫组织化学对最初的CNB进行了重新评估。虽然大多数肿瘤细胞E-钙黏蛋白呈阳性，但一小片显示硬癌亚型样形态的区域E-钙黏蛋白呈阴性。因此，我们将诊断修订为混合性IDC-ILC。IDC和ILC之间不同的化疗敏感性可能有助于解释这一现象。
