Gastrointestinal bleeding is rarely caused by metastatic gastrointestinal lesions, among which duodenopancreatic metastasis from the breast cystosarcoma phylloides is even rare. The radiological features of duodenopancreatic metastasis by cystosarcoma phylloides of breast have not been reported previously. Gastrointestinal endoscopy is the initial modality of choice for GI bleeding by the virtue of direct inspection of mucosal details; while imaging studies are requested to assess the submucosal extent of the lesion. Occasionally, imaging studies are also used to disclose organic gastrointestinal lesion invisible on endoscopy. Herein, we report such a case of gastrointestinal bleeding due to metastatic breast cytosarcoma phylloides.