Colonic Metastasis from Breast Cancer: A Case Report and Review of the Literature

Background: Breast cancer often metastasizes to the lungs, bones, liver, and brain, colon metastasis from breast cancer (CMBC) is extremely rare. Case Report: The patient was a 63-year-old female. Mastectomy had been performed for breast cancer (pStage IIB) 15 years earlier at another hospital. Metastasis to the lumbar spine had been detected 4 years prior to referral to us and the patient had undergone hormonal therapy with an aromatase inhibitor. Furthermore, early primary sigmoid colon cancer had been endoscopically resected 2 years before referral. The patient was diagnosed with cancer recurrence in the colon at follow-up examinations performed 2 years after that endoscopic resection. After referral to our hospital, laparoscopic sigmoidectomy was performed. Based on the histopathological examination and immunohistological staining results (positive for cytokeratin 7, GATA-binding protein 3, estrogen receptor and human epidermal growth factor receptor-related 2 (2+); negative for disease fluid protein 15 and caudal-related homeobox 2) the final pathological diagnosis was CMBC. Conclusion: Although extremely rare, the possibility of CMBC should be considered in the case of colonic tumors in patients with a history of breast cancer.