RESUMEN
Gastrointestinal (GI) metastasis from breast carcinoma is a rare occurrence. If metastasis occurs to the stomach/duodenum, it can present with symptoms of gastric outlet obstruction (GOO). Hence, it clinically mimics a variety of benign as well as malignant causes of GOO, including primary malignancy. GI metastasis from breast carcinoma occurs several years after the primary diagnosis and sometimes may be the first presenting symptom. If clinical records are not available, it may be misdiagnosed as poorly differentiated adenocarcinoma on biopsy. A high index of suspicion, subtle histologic clues, and appropriate immunohistochemistry helps in clinching the right diagnosis. Hereby, we report the case of a 55-year-old female who presented with metastasis to the duodenum 8 years post mastectomy which mimicked a primary ampullary/periampullary tumor.