Early HER2-positive breast cancer arising from a fibroadenoma: a case report. Issue 9 (13th September 2021)

• Record Type: Journal Article
• Authors: Fujimoto, Akihiro; Matsuura, Kazuo; Kawasaki, Tomonori; Ichinose, Yuki; Nukui, Asami; Hiratsuka, Miyuki; Asano, Aya; Shimada, Hiroko; Osaki, Akihiko; Saeki, Toshiaki
• Is Part Of: Oxford medical case reports. Volume 2021:Issue 9(2021)
• Publication Date: 2021-09-13
• Subjects: Clinical medicine -- Case studies -- Periodicals; 616.09
• DOI: 10.1093/omcr/omab083
• Languages: English
• ISSNs: 2053-8855

Abstract

ABSTRACT: Breast cancer arising from fibroadenoma (FA) is rare, in which almost all reported cases are human epidermal growth factor receptor 2 (HER2)-negative. This is the first report to describe a case of HER2-positive breast cancer arising from FA that was treated with chemotherapy plus anti-HER2 therapy. In this early case, upfront surgery outcomes guided the selection of appropriate systemic therapy. A 31-year-old woman previously diagnosed with FA experienced tumor growth. Core needle biopsy and imaging studies confirmed a diagnosis of stage IIA HER2-positive invasive ductal carcinoma (IDC) with no evidence of lymph node metastasis (cT2N0M0). Breast-conserving surgery was performed. Pathological diagnosis revealed stage IA IDC with a predominant intraductal component (pT1aN0M0), arising from FA. In conclusion, we encountered an extremely rare case of HER2-positive breast cancer arising from FA in which pathological infiltration was difficult to predict based on preoperative imaging.