Small-Intestinal Metastasis from Breast Cancer Presenting with Gastrointestinal Bleeding: A Case Report

INTRODUCTION: Gastrointestinal metastases from breast cancer are rare, especially in the small intestine, and diagnosis is often difficult due to nonspecific symptoms and limited detectability with standard endoscopy. Intestinal bleeding, although uncommon, may become clinically significant. We report a case of recurrent triple-negative breast cancer in which persistent anemia during sacituzumab govitecan (SG) therapy was attributed to small-bowel metastasis, and small-bowel evaluation using capsule endoscopy and balloon-assisted enteroscopy led to the diagnosis after standard upper and lower endoscopy failed to identify the source of bleeding.