Mucocele of the Appendix

Mucocele of the appendix is an infrequent event, representing 0.3%–0.7% of appendiceal pathology and 8% of appendiceal tumors. It is characterized by a located or diffuse distension of the appendix with a mucus-filled lumen.

We describe 35 cases of mucocele of the appendix diagnosed at Ramón y Cajal Hospital between January 1985 and January 2006.

A total of 21 males and 14 females with a mean age of 52.7 years are described. Most cases manifested as abdominal pain located in right iliac fossa, but 2 cases were incidental findings at CT-scan and 1 at ultrasonography, performed for other reasons. In 4 cases, mucocele coexisted with colorectal cancer and was an incidental finding during laparotomy performed for tumor resection. Ultrasonography and computed tomography (CT) scan helped to achieve a correct diagnosis. Preoperative diagnosis of mucocele was achieved in 29% of the cases; 88% of patients underwent appendectomy, 2 had ileocecal resection, and 2 others underwent right hemicolectomy. Pathology revealed mucous hyperplasia in 34% of the cases, simple mucocele in 29%, cystadenoma in 31%, and cystadenocarcinoma in 2 patients. Two other patients developed adenocarcinoma of the cecum 12 and 33 months after surgery, and one patient developed pseudomyxoma peritonei after 62 months, causing his death.

The pathologist is forced to do an exhaustive study, looking for inadvertent perforations that can change the good prognosis of mucocele. We recommend follow-up of all patients with mucoceles, because sometimes they are associated with colorectal neoplasms and recurrence as pseudomyxoma peritonei.