Intraparenchymal pericatheter cyst. A rare complication of ventriculoperitoneal shunt for hydrocephalus

Intraparenchymal pericatheter cyst is rarely reported. Obstruction in the v entriculoperitoneal shunt leads to recurrence of hydrocephalus, signs of ra ised intracranial pressure and possibly secondary complications. Blockage o f the distal catheter can result, unusually, in cerebrospinal fluid oe dema and/or intraparenchymal cyst around the ventricular catheter which may pro duce focal neurological deficit. We report two cases of distal catheter obs truction with formation of cysts causing local mass effect and neurological deficit. Both patients had their shunt system replaced, which led to resol ution of the cyst and clinical improvement. One patient had endoscopic expl oration of the cyst which confirmed the diagnosis made on imaging studies. Magnetic resonance imaging was more helpful than computed tomography in dif ferentiating between oe dema and collection of cystic fluid. Early recognit ion and treatment of pericatheter cyst in the presence of distal shunt obst ruction can lead to complete resolution of symptoms and signs.