Perforated colonic cancer presenting as intra-abdominal abscess

The various presentations of carcinoma of the colon are well known. Abscess formation occurs in 0.3 to 0.4% and is the second most common complication of perforated lesions. Perforation and penetration of adjacent organs with intra-abdominal abscess formation as the initial presentation is uncommon.

A retrospective analysis was made between January 1998 and December 2003 at the Kaohsiung Medical University Hospital. Six colon cancer patients with intra-abdominal abscess as the initial presentation were enrolled into this study. Among them, two were men and four were women.

During the 6-year period, there were 756 patients with colonic carcinoma but only six of those patients (0.79%) presented with abscess formation as the initial finding. The initial pre-operative diagnosis was ruptured colonic diverticulitis with abscess formation in three patients, and the other three patients were as follows: one ruptured appendicitis with abscess, one right subcutaneous inguinal abscess, and one omphalitis with abdominal wall abscess. Subsequent colonoscopy was performed in two patients, and colon cancer was recognized. The most common associated symptoms/signs were palpable abdominal mass, abdominal pain, and anemia. All of them underwent a one-stage surgical procedure, and adjuvant chemotherapy was given. One patient died of peritoneal carcinomatosis and liver metastases 1 year post-operatively. The other five patients are still alive.

It is difficult to make an accurate diagnosis of abscess formation as the first evidence of colonic carcinoma pre-operatively. The one-stage resection of the lesion seems to be an acceptable treatment. For patients with intra-abdominal abscess, clinicians should be aware of this differential because it is easily ignored pre-operatively.