AUTHOR=Ruan Sibei , Zhou Jian , Tang Rui , Wang Tao , Gao Xia , Mou Lixian , Tang Mingxi 

TITLE=Case Report: Breast ductal carcinoma in situ with microinvasion: a case tracked over 13 years

JOURNAL=Frontiers in Oncology

VOLUME=Volume 15 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1560366

DOI=10.3389/fonc.2025.1560366

ISSN=2234-943X

ABSTRACT=BackgroundNumerous studies have reported considerable heterogeneity in breast ductal carcinoma in situ with microinvasion (DCIS-MI) regarding clinical presentation, progression potential, and treatment strategies.Case presentationIn this work, we report a case of rapidly progressing multiple metastases in a patient with DCIS-MI following conventional treatment. Subsequent fluorescence in situ hybridization (FISH) testing revealed HER2 gene overexpression. After receiving 10 cycles of trastuzumab-targeted therapy, the patient achieved a favorable prognosis and remains stable to date.ConclusionThis case suggests that even patients with microinvasive lesions who are HER2-positive may exhibit unexpected stability under targeted therapy, warranting close surveillance in such cases.