A case of three year-old-male with large abdominal cerebrospinal fluid pseudocyst as late complication of ventriculoperitoneal shunt was presented. When the patient was 8 months old, a V-P shunt procedure was performed for communicating hydrocephalus. The shunt had to be revised two times because of its migration. At the age of 3 years, he was readmitted for abdominal distension and vomiting. A diagnosis of intestinal obstruction was made, and he was treated concervatively. Several days later, lower abdominal mass was recognized on the abdominal plain x-ray film. Ultrasonotomography demonstrated the tip of catheter in the cystic cavity, and preoperative diagnosis of abdominal CSF preudocyst was made. Intra-abdominal complications following V-P shunt procedure are more common than previously reported, but abdominal CSF pseudocyst is rare, that is seem in about 1% of all V-P shunt cases. 44 cases were totalized in the literature including our case. Analysis of these cases shows some common aspects as follows. 1) Most cases have previous history of repeated shunt infections and/or shunt revisions. 2) 82% (28/34) of all cases are infants and children under 8 years of age. 3) Cultures of cystic fluid revealed Staphylococcus epidermidis or Staphylococcus aureus in most of cases. 4) Cyst walls are thick and fibrous, and directly surrounded by loops of intestine or other organs. 5) Recurrence of the cyst was found in the cases that V-P shunt was inserted simultaneously during the operation of the cyst. It is concluded that the pathogenesis of CSF pseudocyst is suspected to be the isolation of catheter tip resulting from inflammatory reaction or intra-abdominal procedures, and then the fluid accumulation and development of cyst wall will follow. Abdominal ultrasonotomography and computed tomography are much useful for the diagnosis of this disease, and the tip of catheter in the cystic cavity could be identified by these methods. Cystotomy and drainage with external ventricular drainage or V-A shunt are suggested for the treatment. Simultaneous replacement of a new V-P shunt should be avoided. Finally, abdominal CSF pseudocyst should be included in the differential diagnosis for every case of an acute abdominal complications with V-P shunt.
