There have been many reports on various mechanical complications after shunt operations in children with hydrocephalus such as catheter fracture, obstruction, disconnection, dislocation and so on. However, there are no previous reports regarding subcutaneous mass formation due to cerebrospinal fluid (CSF) pseudocyst from direct puncture injury. The authors report with a review of the literature a case of a child with ventriculoperitoneal shunt who developed a neck mass after catheterization of the neck vein. The authors also advocate that percutaneous procedures in the vicinity of shunts be avoided whenever possible to prevent the possibility of CSF leakage resulting in pseudocyst formation.