Foreign body granuloma secondary to ventriculo-peritoneal shunt: a rare scenario with a new insight.

Ventriculo-peritoneal shunts are used extensively for the management of hydrocephalus and frequently present with complications such as shunt blockage and infection. Cerebrospinal fluid (CSF) eosinophilia and allergic responses to the shunt itself are rare, poorly understood but increasingly recognised complications. Here, the authors describe a child who required multiple shunt revision surgeries due to extensive scalp tenderness overlying the shunt tubing and persistent severe headaches despite having a normal working shunt and no CSF infection or eosinophilia. Histological investigation of excised tissue during the last shunt revision demonstrated fibrosis with scar tissue and chronic inflammatory infiltrate with foreign body giant cells and few abortive granulomata. This was felt to represent a foreign body reaction to the shunt. A hypoallergenic ‘extracted' shunt was trialled (extracted Delta® valve and extracted ventricular and peritoneal catheters; Medtronic) and the child has had no further shunt revisions and is currently asymptomatic 1 year after the insertion.