A Rare Case of Intraparenchymal Cerebrospinal Fluid Cyst Associated With Ventriculoperitoneal Shunt in an Adult Patient.

Here we are reporting a rare phenomenon associated with ventriculoperitoneal (VP) shunt in the adult patient, namely, the development and finding of intraparenchymal pericatheter cerebrospinal fluid cyst. Our patient had a VP shunt placed for idiopathic intracranial hypertension 16 years ago before presentation to the hospital. The patient was admitted to the hospital for headache for past three weeks with the initial CT scan showing encephalomalacia and vasogenic edema. MRI showed the presence of a 4-cm intraparenchymal cyst in the right frontal lobe with surrounding vasogenic edema. The patient underwent two surgeries with the initial surgery for the drainage of cyst and second surgery for the placement of the cystoperitoneal shunt. Catheter-associated cysts are easily misdiagnosed due to their similarity in appearance to abscesses and other malignancies on imaging, and there are no guidelines yet on their evaluation and management. This is a unique case as the pericatheter cyst developed 16 years after the initial VP shunt placed. Given the rarity of this presentation, we hope that our case report can contribute to the development of guidelines and treatment options in adults with long-standing VP shunts.