Appendiceal mucocoeles occurs when there is abnormal accumulation of muocus within the appendix. The tenacious and viscous mucous causes obstruction of the appendiceal neck and results in dilatation of the lumen.
The reported prevalence is at appendectomy is 0.2 - 0.3%.
Results from chronic appendiceal obstruction that may be caused by either benign or malignant lesions:
- mucosal hyperplasia
- mucinous neoplasms
- appendiceal carcinoid
- adjacent caecal tumour
Fluoroscopy - Barium enema
If a contrast examination is performed, there is usually non-filling or partial-filling of the appendix. Where there is a large mucocoele, the associated mass effect can cause indentation or lateral displacement of the caecum.
The presence of an "onion sign" (sonographic layering within a cystic mass) is considered a highly suggestive feature 2,6.
- typically seen as a well-circumscribed, low-attenuation, spheric or tubular mass contiguous with the base of the caecum
- the finding of curvilinear mural calcification suggests the diagnosis, but is seen in less than 50% of cases
- intra-luminal bubbles of gas, or an air-fluid level within a mucocele suggest the presence of superinfection, which can occur in both benign and malignant mucocoeles
Treatment and prognosis
Treatment is usually surgical.
Rupture of an appendiceal mucocoele may lead to pseudomyxoma peritonei
- 1. Bennett GL, Tanpitukpongse TP, Macari M et-al. CT diagnosis of mucocele of the appendix in patients with acute appendicitis. AJR Am J Roentgenol. 2009;192 (3): W103-10. doi:10.2214/AJR.08.1572 - Pubmed citation
- 2. Caspi B, Cassif E, Auslender R et-al. The onion skin sign: a specific sonographic marker of appendiceal mucocele. J Ultrasound Med. 2004;23 (1): 117-21. J Ultrasound Med (full text) - Pubmed citation
- 3. Bartlett C, Manoharan M, Jackson A. Mucocele of the appendix - a diagnostic dilemma: a case report. J Med Case Rep. 2007;1 : 183. doi:10.1186/1752-1947-1-183 - Free text at pubmed - Pubmed citation
- 4. Madwed D, Mindelzun R, Jeffrey RB. Mucocele of the appendix: imaging findings. AJR Am J Roentgenol. 1992;159 (1): 69-72. AJR Am J Roentgenol (citation) - Pubmed citation
- 5. Attarde V, Patil P, Apte A et-al. Sonographic appearance of a giant appendicular mucocele. J Clin Ultrasound. 2011;39 (5): 290-2. doi:10.1002/jcu.20809 - Pubmed citation
- 6. Francica G, Lapiccirella G, Giardiello C et-al. Giant mucocele of the appendix: clinical and imaging findings in 3 cases. J Ultrasound Med. 2006;25 (5): 643-8. J Ultrasound Med (citation) - Pubmed citation
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Mucocoele of the appendix||✓|