ABSTRACT
Usual sources of subphrenic abscess with intestinal fistula are previous abdominal operation, inflammatory bowel disease and malignancy. Reported cases of intestinal fistula caused by adenocarcinoma were complicated by direct invasion. In this report, a 70-year-old male had a subphrenic abscess with intestinal fistula and the cause was a metastatic adenocarcinoma of unknown origin. As far as we know, this has not been reported previously in the literatures. The abscess went on chronic course for six months because intermittent administration of antibiotics modified its clinical presentation. The fistulous tract between the abscess and ileum was demonstrated by tubogram via the drainage catheter in abscess. The patient underwent surgical treatment because the cause of fistula was obscure. Invasion of the ileum by metastatic adenocarcinoma was diagnosed by the histologic examination of surgical specimen. Therefore, when a fistula develops without any apparent cause, there is a possibility of malignancy, and surgical approach must be considered. An early surgical approach will prevent the delay in treatment and reduce the mortality.