Background: Appendiceal tumors are difficult to detect and often present with evidence of peritoneal carcinomatosis on initial diagnosis. Radiographic studies may identify appendiceal enlargement, appendiceal mass, or mucinous ascites suggestive of appendiceal carcinoma. Exploratory laparotomy is often necessary to manage appendiceal perforation and is the most often used modality to obtain tissue for diagnosis. Incidental detection of appendiceal mucocele on colonoscopy has been reported in case reports and case series in the medical literature, however, there are no published reports regarding the effectiveness of colonoscopy in detection of adenocarcinoma of the appendix.
Aims: The aim of this study is to determine the diagnostic yield of colonoscopy in detecting lesions in patients with known mucinous adenocarcinoma of the appendix.
Methods: 130 consecutive patients with histologically confirmed peritoneal carcinomatosis secondary to mucinous adenocarcinoma of the appendix presenting to our institution for intraperitoneal heated chemotherapy (IPHC) between February, 1993 and August, 2006 were enrolled. The medical record was reviewed for report of colonoscopy performed within one calendar year prior to presenting for treatment evaluation.
Results: Colonoscopic data was available for 23 patients. The average age of patients presenting for IPHC was 52 years. The average age of patients with colonoscopy was 54. Appendiceal lesion was detected in 1 patient (4.3%). Cecal polyps were detected in 3 patients (13%). Extrinsic compression was detected in 2 patients (8.7%). Colonic polyps were present in 12 patients (52%). No colonoscopic findings were detected in 9 patients (39%).
Conclusions: Colonoscopy does not detect an appendiceal lesion in 96% of patients with known mucinous adenocarcinoma of the appendix. We found that close to half of patients with appendiceal adenocarcinoma have synchronous colonic polyps. Based on this finding, all patients with diagnosis of appendiceal adenocarcinoma should be evaluated with colonoscopy to screen for synchronous colonic polyps.
Colonoscopic findings

Colonoscopic findings	Number of patients with findings	Incidence of findings (%)
No abnormality	9	39%
Colonic polyps	12	52%
Cecal polyps	3	13%
Appendiceal lesions	1	4.3%
Extrinsic compression of colon	2	8.7%