A case of abdominal CSF pseudocyst associated with silicone allergy.

CASE REPORT: The authors present a case of a patient with an abdominal CSF pseudocyst that resulted from an allergic reaction to silicone. The patient underwent repair surgery of the meningomyelocele associated with the Chiari II malformation, and the V-P shunt was instituted at 6 months of age. A formation of the abdominal CSF pseudocyst and the consequent shunt malfunction were observed 40 days after the V-P shunt. An increase in the number of the peripheral eosinophils and serum immunoglobulin E (IgE), and an infiltration of eosinophils in the specimen harvested from the pseudocyst wall suggested an allergic reaction as the cause of the pseudocyst. A sixth operation to revise the V-P shunt was performed using the shunt system made of "extracted silicone", which was produced extracting the allergic substances. OUTCOME: The serum IgE was normalized after surgery and the abdominal CSF pseudocyst has not recurred for 22 months.