A case of recurrent invasive lobular carcinoma of the breast found as metastasis to the duodenum.

A 57-year-old woman underwent modified radical mastectomy for cancer of the left breast (stage IIB) in February 2004. Invasive lobular carcinoma was diagnosed on histopathological examination. The patient received postoperative chemotherapy and endocrine therapy on an outpatient basis and was observed. In August 2005, anorexia developed. Blood chemical tests showed elevated levels of liver enzymes and bilirubin. Computed tomography (CT) of the abdomen revealed an enlarged duodenum and dilated intrahepatic biliary and pancreatic ducts. Upper gastrointestinal endoscopy showed edema of the duodenum. A biopsy yielded a diagnosis of poorly differentiated adenocarcinoma. Duodenal carcinoma was suspected, and a pancreatoduodenectomy was performed. Duodenal metastasis from invasive lobular carcinoma was diagnosed on postoperative histopathological examination. After surgery, the patient recovered uneventfully and was discharged from the hospital. In March 2006, bilateral hydronephrosis apparently caused by peritoneal metastasis developed, and she subsequently died. Invasive lobular carcinoma is characterized by the development of gastrointestinal metastases and is rarely detected before autopsy. We describe our experience with a patient in whom invasive lobular carcinoma of the breast with metastasis to the duodenal wall was definitively diagnosed on laparotomy.