Learning Radiology xray montage

Pseudomyxoma Peritonei
Submitted by Paurush Shah, MSIV

General Considerations

  • Diffuse collections of gelatinous material in the abdomen and pelvis and mucinous implants on the peritoneal surfaces
  • In almost all cases, it is from a ruptured mucinous tumor of the appendix
    • Spectrum from more benign to more malignant findings
  • Other causes may include tumors of the large and small bowel, lung, breast, pancreas, stomach, bile ducts, gallbladder, and fallopian tubes/ovary
  • More common in females
  • Results in mass effect on organs
    • Also known as “Jelly Belly”

Clinical Findings

  • Indolent course
  • Most common finding in both males and females is increasing abdominal girth (40%)
    • Next most common in males is inguinal hernia (25%)
    • Next most common in females are bilateral or unilateral ovarian masses

Imaging Findings

  • On CT scan, mucinous material has similar density to fat and appears heterogeneous.
  • Scalloped surface of the liver, spleen, and mesentery
  • Rim-like calcifications are common
  • Undersurface of the diaphragm may be thickened by large cystic masses of mucinous tumor
  • Peripheral location of tumor within the abdomen with central displacement of the small bowel and mesentery
  • Narrowing, but usually not obstruction, of lumen of GI tract at
    • Pylorus
    • Ileocecal valve
    • Pouch of Douglas
  • Usually spares the small bowel
  • Ultrasound may show large, immobile ascites with septations and increased echogenicity

Differential Diagnosis

  • Peritoneal mucinous carcinomatosis
    • Produces picture similar to pseudomyxoma peritonei
    • Implanted (signet-ring) cells are malignant
    • Extensive small bowel implantation
    • Worse prognosis


  • Repeated surgical debulking to decrease abdominal pressure and remove mucinous material build-up
    • Not curative
  • Heated intraperitoneal chemotherapy is controversial and is being investigated currently


  • Mucous buildup, increased abdominal pressure, bowel obstruction, renal failure, death


  • Median survival of 2 years has been reported although newer treatments are improving survival
  • 25% mortality due to intestinal obstruction and renal failure

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Pseudomyxoma Peritonei

Pseudomyxoma peritonei. Axial contrast-enhanced CT images of the abdomen and pelvis
demonstrate lobulated, low-attenuation soft tissue masses scalloping the borders of the liver, spleen and along mesentery. The cause was a mucin-producing tumor of the appendix.

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Swanson, Richard et al. “Cancer of the appendix and pseudomyxoma peritonei.” Jan 13, 2009 uptodate.com

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