Appendiceal mucinous cystadenoma

Appendiceal mucinous cystadenomas are rare tumours of the appendix. They are considered a benign equivalent of an appendiceal mucinous cystadenocarcinoma.

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:

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Article information

rID: 23740
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Mucinous cystadenoma of appendix
  • Appendiceal mucinous cystadenomas
  • Mucinous cystadenoma of the appendix
  • Mucinous cystadenomas of the appendix
  • Appendiceal mucinous cystadenomas

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