The purpose of this educational exhibit is to: 1. Outline the various causes of appendiceal mucocele. 2. Describe and illustrate the imaging appearances of appendicealmucoceles of different etiologies. 3. Describe and illustrate complications of appendiceal mucoceles and their treatment. 4. Describe and illustrate other conditions which may mimic a mucocele, outlining key imaging features which may help to differentiate these prior to surgery.

‘Appendiceal mucocele’ is the term used to describe abnormal distention of all or part of the appendix by sterile mucus within the lumen. Mucoceles may present at any age, though are most frequent in middle-aged patients, with a female predominance. Mucoceles result from hypersecretion of mucus and /or chronic obstruction of the appendiceal lumen by a variety of causes, including; tumor appendicolith adhesions/fibrosis foreign body Patients may present in a variety of ways. The most common are; abdominal pain palpable mass symptoms of local pressure...

Imaging Contrast-enhanced CT is the imaging investigation of choice, though mucoceles are often seen on other imaging modalities such as MR, ultrasound or virtual colonography. Simple appendiceal mucocele A simple appendiceal mucocele, resulting from non-neoplastic causes such as obstructing appendicolith or adhesions/fibrosis, appears as a distended intraperitoneal cystic structure, arising from the cecal pole.These tend to be smaller, rarely exceeding 2cm diameter, and tend not to have mural calcification. Fig. 1 Fig. 2Fig. 3 Fig. 4 Appendiceal mucocele secondary to mucin hyper-secretion The majority of...

Conclusion Correct identification of an appendiceal mucocele on imaging studies and, where possible, its underlying cause is important to ensure the patient receives appropriate treatment from the outset.

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