Mucocele of the appendix: ultrasonographic and CT findings

Abstract.

Background: Mucocele of the appendix is a rare disease entity, but preoperative diagnosis is very important. With the advent of ultrasonography (US) and computed tomography (CT), it has been possible to preoperatively diagnose mucocele of the appendix. We describe the spectrum of US and CT findings of mucocele of the appendix and the differential points from mimicking diseases.

Methods: We evaluated 17 patients with pathologically proven mucocele of the appendix by using US and CT. Pathologic diagnoses of 17 patients were mucinous cystadenoma in 11 patients, mucinous cystadenocarcinoma in two, and mucosal hyperplasia in four. We analyzed morphologic characteristics of mucocele of the appendix at US and CT.

Results: The typical US finding were a cystic mass with variable internal echogenicity, layered wall, and calcification in the wall. The CT finding was a well-encapsulated cystic mass with a wall of variable thickness. Both cases with focal nodular solid enhancing portion in the wall on CT were pathologically proven as mucinous cystadenocarcinoma.

Conclusion: US and CT were useful methods in diagnosing mucocele of the appendix and differentiating this condition from mimicking diseases. Nodular enhancing lesion in the wall of the mucocele may be a finding suggestive of malignant cause of mucocele.