Ventricular Migration of Vitreous Silicone Oil Masquerading as a Ruptured Colloid Cyst

The ventricular migration of vitreous silicone oil (SiO) is rare and can easily be mistaken for intraventricular hemorrhage or a ruptured colloid cyst. We report here the case of an adult male who was misdiagnosed with a ruptured colloid cyst and was subsequently found to have ventricular migration of vitreous SiO. A 57-yearold male presented unresponsive following a respiratory arrest and underwent a head computed tomography (CT) scan that demonstrated multiple ovoid hyperdensities in the ventricular system, which was concerning for a ruptured colloid cyst. He was transferred to our institution for neurosurgical evaluation. Magnetic resonance imaging (MRI) was performed and demonstrated widespread abnormal diffusion restriction throughout the cortex and basal ganglia, consistent with anoxic brain injury secondary to hypoxic respiratory arrest. The MRI also demonstrated an abnormal signal in areas corresponding with the previously identified intraventricular lesions, which did not layer posteriorly. Given that the MRI sequence signals of the lesions in the ventricular system matched perfectly with the signals of the somewhat deflated SiO within the globe, these multiple ovoid lesions on imaging were most consistent with the migration of SiO from the vitreous body of the right globe into the ventricular system. This case demonstrates a diagnostic error that can occur in emergent settings because of the broad differential diagnosis for cerebral ventricular hyperdensities. A ruptured colloid cyst was considered the reason for transfer, with the anticipation of neurosurgical intervention, but further imaging demonstrated that this was an incidental finding in this patient who presented in extremis. Awareness of this rare clinical condition can prevent overutilization of resources and unnecessary interventions.