A case of adenocarcinoma in lung proceeding to metastasis in the small intestine is reported here. A 70-year-old woman was admitted to hospital with general fatigue, constipation and body weight loss. Laboratory data indicated anemia and a high level of CEA. From a chest X-ray and CT, we suspected lung tuberculosis, but results of cultures and a bronchoscopy were negative. Results of gastroduodenal endoscopy, colonoscopy and abdominal CT showed no reason for anemia or CEA elevation. Barium study of the small intestine showed a tumor about 200cm on the distal side of the ligament of Treitz. We performed partial resection of the small intestine, due to intestinal obstruction and procession of anemia. Histological examination of resected tissue suggested metastatic adenocarcinoma. Therefore we tried CT-guided biopsy of the lung tumor to find the primary lesion. Histological examinations of the biopsy tissue revealed primary lung adenocacinoma. Although metastasis of the small intestine progressing after lung cancer has a very poor prognosis, some patients still live long after the operation. Therefore it is essential to examine the digestive tract for the suspected small intestine metastasis, and operation as soon as possible.
