An 81-year-old man who had been aware of a right anterior abdominal mass for 1 week was admitted to our hospital on July 3, 1999, after the mass had perforated and was secreting mucinous purulent material. Computed tomography clearly showed an anterior abdominal wall abscess and a large intraabdominal tumor that contained a fistula-like structure. Barium enema revealed an apple-core sign at the transverse colon, with a fistula that connected the colon to the abscess cavity. Transverse colonic cancer complicated by an anterior abdominal wall abscess was diagnosed, and an extended right hemicolectomy was performed. We did not perform en bloc excision of the full thickness of the anterior abdominal wall, including the abscess, because the defect was determined to be too large to repair. Thus, when curative resection is not feasible, as in our patient, resection of the primary tumor with en bloc partial resection of the adherent parietal wall should be performed if possible, as this procedure has the potential to improve the postoperative quality of life of the patient.