Human Epidermal Growth Factor Receptor 2-positive Mucinous Carcinoma with Signet Ring Cell Differentiation, Which Showed Complete Response after Neoadjuvant Chemotherapy

• Published in: Journal of breast cancer Vol. 22; no. 2; pp. 336 - 340
• Main Authors: Jang, Yunjeong, Cho, Eun Yoon, Cho, Soo Youn
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Breast Cancer Society 01.06.2019; 한국유방암학회
• Subjects: Case Report; 일반외과학; Adenocarcinoma, mucinous; Neoadjuvant therapy; Breast neoplasms; Receptor, ErbB-2; Carcinoma, signet ring cell
• ISSN: 1738-6756; 2092-9900
• DOI: 10.4048/jbc.2019.22.e17

Mucinous carcinoma (MC) is a rare subtype of breast cancer, which is composed of tumor cells floating in the abundant extracellular mucin. This form of cancer is usually estrogen receptor/progesterone receptor positive and human epidermal growth factor receptor 2 (HER2) negative. Here, we present a case of HER2-positive MC with an unusual signet ring cell differentiation. It is very rare that a breast tumor consists entirely of signet ring cells. The tumor showed pathologic complete response (pCR) after neoadjuvant chemotherapy with trastuzumab and pertuzumab. pCR of HER2-positive MC has rarely been described in literature. It is important to consider the biological heterogeneity of MCs for effective management.