They may be histologically present in around 0.3% appendiceal resection specimens 3.
A commonly described clinical presentation is right iliac fossa pain, similar to that of an acute appendicitis. Around 25% of patients can be asymptomatic 2.
It is characterised by villous adenomatous changes of the appendiceal epithelium associated with marked distension of the appendiceal lumen with mucin. This can typically result in an appendiceal mucocoele.
Differentiation between cystadenoma and cystadenocarcinoma of the appendix can be difficult. Size, density and wall thickness of these mucoceles can be similar between the two groups. Furthermore, calcification, internal septations, periappendiceal fat stranding and intraperitoneal free fluid is nonspecific.
The presence of:
- soft tissue thickening (internal soft tissue attenuation nodularity of mucoceles)
- wall irregularity
- pseudomyxoma peritonei
have been shown to be the most specific markers in differentiating between benign and malignant groups with these three features more suggestive of malignancy 6.
Recognised complications include:
- rupture (which may result in pseudomyxoma peritonei)
- 1. Pickhardt PJ, Levy AD, Rohrmann CA et-al. Primary neoplasms of the appendix: radiologic spectrum of disease with pathologic correlation. Radiographics. 2003;23 (3): 645-62. Radiographics (full text) - doi:10.1148/rg.233025134 - Pubmed citation
- 2. Ng SS, Lee JF. Mucinous cystadenoma of the appendix. Can J Surg. 2009;52 (2): 158-9. Free text at pubmed - Pubmed citation
- 3. Zagrodnik DF, Rose DM. Mucinous cystadenoma of the appendix: diagnosis, surgical management, and follow-up. Curr Surg. 2003;60 (3): 341-3. doi:10.1016/S0149-7944(02)00728-6 - Pubmed citation
- 4. Lo RH, Kan PS. Appendiceal mucinous cystadenoma presenting as "porcelain" appendix with myxoglobulosis-a rare cause of a right lower quadrant mass. Singapore Med J. 1998;39 (4): 174-6. Pubmed citation
- 5. Honnef I, Moschopulos M, Roeren T. Appendiceal mucinous cystadenoma. Radiographics. 2008;28 (5): 1524-7. Radiographics (full text) - doi:10.1148/rg.285075160 - Pubmed citation
- 6. Wang H, Chen YQ, Wei R et-al. Appendiceal mucocele: A diagnostic dilemma in differentiating malignant from benign lesions with CT. AJR Am J Roentgenol. 2013;201 (4): W590-5. doi:10.2214/AJR.12.9260 - Pubmed citation
The appendix can be affected by numerous inflammatory, infectious and neoplastic conditions:
- appendiceal mucocoele
neoplasms of the appendix
- appendiceal adenoma
- appendiceal adenocarcinoma
- appendiceal lymphoma
- appendiceal mucinous cystadenoma
- appendiceal mucinous adenoma
- appendiceal mucinous cystadenocarcinoma
- appendiceal mucinous adenocarcinoma
- appendiceal neuroendocrine tumours