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

Treatment

• 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

Complications

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

Prognosis

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

Pseudomyxoma peritonei. Axial contrast-enhanced CT images of the abdomen and pelvis
demonstrate lobulated, low-attenuation soft tissue masses scalloping the border of the liver (left) and a mass in the right lower quadrant representing the primary appendiceal tumor.
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Swanson, Richard et al. “Cancer of the appendix and pseudomyxoma peritonei.” Jan 13, 2009 uptodate.com

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