From the Breast to the Bowel: An Unconventional Metastatic Presentation

Breast cancer is the most common cancer in women. The common sites of metastasis include the lungs, liver, and, infrequently, the gastrointestinal (GI) tract. A 72-year-old Caucasian female presented to the hospital with nausea and vomiting, diarrhea, intermittent abdominal pain, and unintentional weight loss. She had had a past medical history of bilateral lobular breast carcinoma and severe iron-deficiency anemia treated with iron transfusions. On arrival, the examination was significant for hypotension and pallor. Laboratory investigations revealed abnormal liver enzymes and raised tumor markers Ca-125 and carcinoembryonic antigen. Imaging studies established a diagnosis of distal small bowel obstruction. The surgical intervention showed the presence of a small bowel tumor, the biopsy findings of which were consistent with metastatic breast cancer, with ER and PR positive but HER-2 negative. She was managed with a selective estrogen receptor degrader and CDK4/6 inhibitor and has been in remission since. Metastasis to the small bowel from the breast is a very rare occurrence. Clinicians should thus maintain a modest amount of suspicion when encountering an uncommon GI presentation of primary breast malignancy. We describe the case of metastatic breast cancer with an atypical GI presentation.