Mucocoele of the Appendix

• Overdistension of the appendix with mucous 2° to luminal obstruction by fecalith 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
• 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 spheres 

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