Mucocele of the Appendix

  

• Overdistension of the appendix with mucous 2° to luminal obstruction by fecolith or foreign body, carcinoid or endometriosis
• Mean age - 55 years
• M:F = 1:4
• Very rare
• Associated with
  • Colonic adenocarcinoma
  • Mucin-secreting tumor of ovary
• Clinical
  • Asymptomatic (25%)
  • Acute or chronic right lower quadrant pain
• Globular, smooth-walled mass protruding into cecum

Mucocele of the appendix - CT shows low attenuation
smooth-walled mass projecting into cecum in region of appendix

• Peripheral, rim-like calcification may occur
• Low attenuation content on CT
• US
  • Purely cystic
  • Cystic with fine internal echoes
  • Complex cystic mass with high-level echoes
  • Gravity-dependent echoes = layering of protein macroaggregates / inspissated mucoid material
• May rupture and produce pseudomyxoma peritonei
  • May produce bowel obstruction
• Myxoglobulosis is a rare variant of mucocoele in which there are pearly white balls of mucous mixed with other mucous in a mucocoele
  • Usually asymptomatic
  • May present as appendicitis
  • Mass contains multiple small, rounded, nonlaminated calcified sphere

   

Dahnert 4^th Edition