Duodenal metastasis from lobular breast cancer presenting as painless obstructive jaundice

Breast cancer is the most common invasive malignancy among women and represents the second leading cause of cancer-related mortality in this population, following lung cancer. While metastases typically involve the bones, liver and lungs, less common metastatic sites have also been documented. Metastatic involvement of the pancreas or duodenum from an extrapancreatic primary tumour is rare, accounting for less than 3% of all pancreatic and periampullary malignancies. We report a case of isolated ampullary metastasis originating from invasive lobular breast carcinoma in a female patient in her late 50s, more than a decade after the initial diagnosis, accompanied by a review of the relevant literature. Given the limited number of published cases, this report underscores the importance of considering metastatic breast cancer in the differential diagnosis of women presenting with obstructive jaundice, particularly in the presence of a relevant clinical history.