[A Case of Solitary Metastasis to the Small Intestine from Sigmoid Colon Cancer after Treatment of Seven Multiple Cancers].

A 75-year-old woman who had undergone a Hartmann's operation for sigmoid colon cancer 2 years ago was hospitalized because she experienced small bowel obstruction several times. She had a treatment history of 6 other cancers, including 5 gastrointestinal tract cancers. However, the obstruction was relieved by conservative therapy each time. In September 2015, she was hospitalized for ileus. Abdominal computed tomography revealed that the lumen of intestine was partially dilated. Subsequently, a long tube was inserted, but the dilatation of the small intestine was not fully recovered. She was diagnosed with small intestinal obstruction due to adhesion, and she underwent an operation in October 2015. During the laparotomy, she was diagnosed with adhesion due to an intestinal tumor, and a partial intestinal resection, including the entire tumor, was performed. Because the tumor appearance and histological findings were very similar to those of sigmoid colon cancer, the tumor was diagnosed as a solitary metastasis of sigmoid colon cancer to the small intestine. Generally, peritoneal dissemination causes metastasis of colon cancer to the small intestine. However, this is a rare case because the lymphatic system or extra-wall invasion was the most likely cause of metastasis. Ileus repeating the improvement exacerbation, an examination must be performed while considering possible intestinal tumors, especially for a patient previously treated for multiple gastrointestinal cancers.