Acute Appendicitis and Small Bowel Obstruction Secondary to Metastatic Breast Cancer

Breast cancer is the most common cancer in women; it is well-known to metastasize to lymph nodes, lungs, liver, brain, and bones. However, luminal gastrointestinal metastasis is rare, especially to the appendix. Herein, we report a case where cancer metastasized to the ileum and appendix, causing acute appendicitis and small bowel obstruction. This is a 44-year-old female with a history of stage IV metastatic breast cancer to bones, lungs, and ovaries, presented with acute abdominal pain for one day. Her abdomen was soft, distended with generalized tenderness. Computed tomography (CT) of the abdomen and pelvis showed a partial small bowel obstruction and swollen appendix. After her symptoms worsened on conservative treatment, she was taken to the operating room where she was found to have a markedly dilated ileum with signs of acute appendicitis, so she underwent ileocecectomy, appendectomy, and lysis of adhesions. Pathology showed metastatic breast cancer in the appendix with findings consistent with acute appendicitis. She tolerated surgery well without complications. In conclusion, small intestinal and appendiceal metastases of breast cancer are very rare though they should be considered in the differential diagnosis in cancer patients presenting with acute abdominal pain.