Intraventricular silicone oil mimicking a colloid cyst

We report a case where intraventricular migration of silicone oil occurred into the third ventricle, mimicking the presence of a colloid cyst. To the best of our knowledge, this is the first case reported where intraventricular silicone oil (SiO) presented at the foramen of Monro, resembling the radiological appearance of a colloid cyst. The systemic dissemination of silicone oil is a very rare complication of intravitreal SiO administration that is used for providing a mechanical tamponade that maintains the retinal attachment following repair of a retinal detachment. The imaging findings that are characteristic of the presence of intraventricular silicone oil are its usual dissemination in a nondependent location and the accompaniment of changes in its location based on changes in the patient's position.