Metastatic ductal carcinoma of the breast to colonic mucosa.

Breast cancer is the most common malignancy among women, while invasive ductal carcinoma is the most common type of invasive breast cancer. Metastatic spread to the colon and rectum in breast cancer is rare. This report describes a case of a 69-year-old woman with metastatic ductal breast cancer to the rectosigmoid, presenting as an incidental finding on screening colonoscopy. The breast carcinoma was first diagnosed 2 years prior. Colonic biopsies from colonoscopy confirmed metastatic adenocarcinoma consistent with a breast primary. Ultimately her clinical condition worsened as she developed malignant ascites, a small bowel obstruction, and new bone metastases, and the patient succumbed to her illness. Cases of metastatic breast cancer to the gastrointestinal tract have predominantly been lobular breast carcinoma. Increased awareness of colonic metastasis may lead to more accurate diagnosis and earlier systemic treatment.