Pseudomyxoma peritonei

Case contributed by Michael P Hartung
Diagnosis certain


Worsening abdominal distension. Concern for malignacy.

Patient Data

Age: 60 years
Gender: Male

Diffuse, extensive peritoneal disease. Extensive scalloping and deformity of the liver and spleen with low attenuation material. Thick omental caking throughout the abdomen up to 4.7 cm anterior-posterior in the mid abdomen. Numerous sites serosal implants including stomach, large bowel, and small bowel. Multiple areas of peritoneal nodularity and thickening. No small bowel obstruction is identified.

There are a few small calcifications with possible mass or implants in the region of the appendix in the right lower quadrant. 



Final pathology diagnosis from omental biopsy: Mucinous and low-grade neoplastic gastrointestinal type epithelium. 

The abundant mucin and scant low-grade neoplastic gastrointestinal type epithelium are consistent with pseudomyxoma peritonei. Recommend examination of the appendix as well as other sites of the GI tract for primary source.

Case Discussion

In this case, the extensive scalloping of the liver and spleen suggest rupture of a mucinous neoplasm resulting in pseudomyxoma peritonei, rather than broadly stating there is peritoneal carcinomatosis.

A close look in the right lower quadrant reveals a few calcifications with an irregular appendix or implants, suggesting ruptured appendiceal mucinous adenocarcinoma as the cause (which also happens to be the most common cause of this condition).

Because pathologic diagnosis is ultimately required, it is appropriate to guide the ordering physician toward omental biopsy, which is very safe and can be performed under ultrasound. 

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