Appendiceal mucocoele

Case contributed by Hoe Han Guan


Right sided vague abdominal pain for the past 5 years. Noticed a palpable mass over the right iliac fossa for the last 6 months.

Patient Data

Age: 60 years
Gender: Male

A relatively well circumscribed, low attenuation, tubular shape mass seen at the right iliac fossa region. This tubular mass is in contiguous with the base of cecum. A few curvilinear mural calcification seen with enhancing thickened wall and internal septations. No mural nodularity , soft tissue or irregular wall thickening seen within the mass. 

Low attenuation free fluid (attenuation number 0 to 10 HU) seen at the Morison pouch, perisplenic region, bilateral paracolic gutters and the pelvis region. The free fluid is greater in amount over the right iliac fossa. No scalloping of visceral surfaces such as liver and spleen.


Laparoscopic intraoperative image showed peritoneal viscous mucinous fluid.

Case Discussion

Overall CT features are suggestive of appendiceal mucocele. The presence of low attenuation intraperitoneal loculated fluid collection raises the suspicion of pseudomyxoma peritonei (though no scalloping of visceral surfaces in this case). Absence of wall irregularity and soft tissue thickening suggests the benign process. However, surgical excision with HPE correlation is highly recommended for differentiating the benign and malignant processes.

Patient underwent laparoscopic appendectomy.

Histopathology (peritoneal fluid/mucinous fluid): Pseduomyxoma peritonei

Histopathology (appendectomy): Low grade mucinous cystadenoma. Negative for invasive malignancy.

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