Online Quiz

CASE 3 ( Closed )

History :
33 / M presented with complaints of pain abdomen and abdominal distension.


Review the imaging series and give your diagnosis.
What are the differentials diagnosis?

Please see the answer below.




Teaching Points:
In a patient with history of VP shunt surgery and Local signs of an intraabdominal mass the possibility of CSF collection should be considered.The most common extracranial complications of ventriculoperitoneal shunt are tube disconnection, blockage of the shunt tip, infection, bowel obstruction and perforation. Uncommon complications described in the literature include subphrenic abscess, small-bowel perforation with secondary formation of a cerebrospinal-enteric fistula, untreatable CSF ascites, migration of the shunt tip to distant locations such as the intrathoracic or subphrenic areas and pseudocyst formation. Peritoneal pseudocyst formation is a rare complication of ventriculoperitoneal shunt. Increased intracranial pressure signs may be evident if the shunt tip has been occluded.

USG/CT also demonstrated a cystic mass in close association with the ventriculoperitoneal shunt with the tip of the shunt lying within the collection.


The most common distal ventriculoperitonealshunt complications include shuntinfection, subcutaneous collection of CSF,peritoneal pseudocyst, bowel perforation, intestinal volvulus, mesentericpseudotumor,migration of the catheter into the pleural cavityand heart, and development of an incisionhernia. Other less-common abdominalcomplications include bowelobstruction secondary to adhesion; subphrenicabscess, cerebrospinal–enteric fistula; untreatableCSF ascites; catheter disconnection;and extraperitoneal retraction of the catheterthrough the mouth, umbilicus, bladder, vagina, anus, or scrotum. Nonentericviscus perforations also can occur and caninvolve multiple organs, such as the gallbladder,stomach, liver, uterus, or urethra. Obstructionof the distal catheter must be treated as anemergency because it can lead to a significantincrease in intracranial pressure, resulting inassociated complications that can cause considerablemorbidity and possibly death.

An abdominal CSF pseudocyst was firstdescribed by Harsh in 1954. Hahn etal.reported that infection was the mostprominent cause of pseudocyst formation(80%) and emphasized that all cases of abdominalpseudocysts should be consideredto be caused by infection until proven otherwise.

The most common intraabdominal response to infection is sheathing of the peritonealcatheter. The CSF draining into thesesheaths may produce large intraabdominal fluid-filled cysts. The infection and subsequenthigh levels of CSF protein, allergic reactions to immunization, liver dysfunction, and tissue reaction against tubingmaterial and CSF protein have beenknown to impair the absorption of CSF andto have a role in pseudocystformation.The time from the last shunting procedureto the development of an abdominal pseudocyst ranges from 3 weeks to 5 years. The CSF pseudocyst caneither move freely within the peritoneal cavityor adhere to loops of small bowel, the serosalsurface of solid organs, or the parietal peritoneum.CSF pseudocysts can be differentiatedfrom ascites by their characteristic displacementof the bowel gas pattern on abdominalfilms and by the absence of shifting dullness. Although sonography and CT can accuratelylocalize abdominal fluid collections,differentiation of ascites from the aforementionedcystic lesions may not be possible.


  • The supine abdominal radiograph showed a subtle soft-tissue–density mass around the ventriculoperitoneal shunt tip.
  • Ultrasound and CT can confirm the diagnosis.
  • Ultrasound shows a well-defined lucent mass with posterior acoustic enhancement. A noninfected cyst will show uniform internal echotexture and septa that often occur in an infected pseudocyst.
  • CT shows a cyst containing homogeneous water-density fluid. It is important to identify the shunt tip within the cyst for confident diagnosis.


Fine-needle aspiration of the localizedCSF collections under sonographicor CT guidance should be performed to increasethe diagnostic yield. Coley et al. reported that although the sonographicallyguided percutaneous aspiration of CSFpseudocyst was not curative, performance ofthis procedure to alleviate the acute symptomsfollowed by elective shunt revision.

If infection is present, the pseudocyst wallshould be excised and the peritoneal shunting catheter removed. Once the shunt tip is removed, the pseudocystgradually collapses because there is nosecretory epithelium present in the cyst. The formation of a CSF pseudocyst is a poorprognostic sign for the usefulness of the peritonealcavity for shunting. Althoughprevious abdominal pseudocyst formationand peritonitis are not contraindications tosubsequent peritoneal shunting in some reports, the CSF had to be diverted toother cavities because of either recurrence ofthe cysts or failure of the peritoneum to absorb fluid. Culture of the tip of the peritonealcatheter was reported to be more sensitivethan culture of the CSF.


  • pancreatic pseudocyst
  • mesenteric cyst
  • mesenteric abscess
  • lymphocoele
  • seroma
  • cystic lymphangioma
  • cystic mesothelioma
  • benign cystic teratoma
  • cystic spindle cell tumour
  • enteric duplication cyst


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