Bone Fragment Granuloma Mimicking a Brain Tumor Following Placement of an Intracranial Pressure Monitoring System

The placement of intracranial pressure (ICP) monitoring system requires drilling an orifice in the skull. Bone fragments can accidentally be inserted into the brain parenchyma while introducing the ICP monitoring system during the procedure. An intracranial granuloma can be subsequently formed if a non-specific reaction is induced and maintained by the inserted bone fragment in the brain parenchyma. These intracranial granulomas may eventually be confused with brain masses on follow-up imaging studies. We present the case of a 65-year-old male who underwent cranial surgery secondary to a severe traumatic brain injury (TBI). An intracranial bolt was initially placed contralaterally to measure the ICP. Eleven years later, a granuloma from a retained bone fragment secondary to the intracranial bolt placement was suspected. The clinical course, radiological investigations, and differential diagnosis are presented.