Pseudomyxoma Peritonnei

Case History: A 75-year-old patient presented with complaints of abdominal distension, generalized abdominal pain and breathlessness upon lying down position for six months. His liver function and renal function tests were within normal limit. Patient was sent for ultrasound examination, USG revealed thickened echogenic peritoneal masses predominantly in right iliac fossa and gross ascites with echogenic particles which (unlike other forms of particulate ascites, such as haemoperitoneum or pus in the peritoneum) do not move. Further USG guided ascites tapping was performed, which showed goblet cells and mucinous ascites. Patient’s ascites was aspirated many times but it recurred multiple times. Further CECT abdomen was performed, which showed gross ascites with internal nonenhancing internal debris causing scalloping of solid viscera of abdomen, like liver and spleen and displacement of small bowel loops centrally and medially and compresses retroperitoneal structures. There was also an ill-defined peripherally enhancing structure noted in RIF, s/o ruptured mucocele of appendix.

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Figure 1. Ultrasound shows thickened echogenic peritoneal masses (large arrow) predominantly in right iliac fossa and gross ascites (small arrow) with echogenic particles.

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Figure 2. Unenhanced CT axial image gross ascites (large arrow),central displacement of small bowel loops (small arrow).

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Figure 3. Contrast enahanced CT axial image gross ascites with nonenhancing internal debris causing scalloping of solid viscera (large arrow), central displacement of small bowel loops and ill-defined peripherally enhancing structure (small arrow) is also noted in RIF, s/o ruptured mucocele of appendix.

Diagnosis: Pseudomyxoma peritonnei

Discussion: Pseudomyxoma peritonei also known as “jelly belly” refers to intraperitoneal accumulation of a gelatinous ascites secondary to rupture of a mucinous tumor. The most common cause is a ruptured mucinous tumor of the appendix/appendiceal mucocoele. Occasionally, mucinous tumors of the colon, rectum, stomach, pancreas and urachal tumors are implicated. There is some ongoing contention as to whether primary ovarian tumors are a frequent source in their own right, or whether in these cases, the appendix is the primary site and the ovarian lesion is metastatic. Diffuse collections of gelatinous material in the abdomen and pelvis and mucinous implants on the peritoneal surfaces are noted. Spectrums from more benign to more malignant findings are present. On imaging, ultrasound shows echogenic peritoneal masses or ascites with echogenic particles which (unlike other forms of particulate ascites such as haemoperitoneum or pus in the peritoneum) do not move and small bowel loops displaced medially, and it may show scalloping of the liver, spleen and, at times, other organs. On CECT low attenuation, often loculated fluid thoughout the peritoneum, omentum and mesentery scalloping of visceral surfaces, particularly the liver scattered (curvilinear or punctate) calcifications may be frequantly present tends to remain localized to peritoneal cavity.

Differential diagnosis must include peritoneal mucinous carcinomatosis; treatment is repeated surgical debulking to decrease abdominal pressure and remove mucinous material build-up; complications are mucus buildup, increased abdominal pressure, bowel obstruction, renal failure and death; prognosis is median survival of two years has been reported although newer treatments are improving survival.

References
Brant WE, Helms CA. Fundamentals of diagnostic radiology. Philadelphia, PA: Lippincott Williams & Wilkins. 2007.
Federle MP, Jeffrey RB, Woodward PJ, et al. Diagnostic imaging: abdomen. Philadelphia, PA: Amirsys; Lippincott Williams & Wilkins. 2009.
Misdraji J. Appendiceal mucinous neoplasms: controversial issues. Arch Pathol Lab Med 2010;134: 864–870.