Appendiceal mucocele with concomitant colonic cancer. Report of two cases.

Purpose: Mucocele of the appendix is an uncommon disorder, usually found incidentally during ultrasonography or radiographic studies. We report two cases of combined appendiceal mucocele and colonic cancer.
Methods: The two cases were analyzed for the clinicopathologic characteristics such as history, presentation, laboratory data, radiologic and endoscopic studies, pathology, and p53 immunoreactivity.
Results: Two patients were diagnosed with an appendiceal mucocele by ultrasound of the abdomen, together with computed tomography. Colonoscopic examination subsequently revealed synchronous colonic adenocarcinoma in both patients. Ileocecal resection following endoscopic polypectomy and a right hemicolectomy was performed for each patient. An appendiceal mucocele was histologically diagnosed as a mucinous cystadenoma. Immunohistochemical detection of abnormally high level of p53 protein was observed in colonic adenocarcinomas of both patients, whereas both appendiceal cystadenomas were negative for p53.
Conclusions: To be remembered is the high frequency of concomitant gastrointestinal tumors in patients with appendiceal mucocele, especially caused by mucinous neoplasms. A total colonoscopic surveillance will afford earlier diagnosis of synchronous colonic cancers in these patients.