Recognizing intraventricular silicone

Retinal detachment with subsequent silicone oil retinopexy is not uncommon. A known complication of silicone retinopexy is intraventricular migration of the intraocular silicone oil. While the oil itself does not result in direct pathology, misdiagnosis may lead to an unnecessary diagnostic workup and possibly predispose the patient to surgery intervention. Silicone oil typically appears hyperdense on computer tomography (CT) and hyperintense on T1-weighted magnetic resonance (MR). These imaging findings may mimic a mass or blood products. However, MR imaging of silicone results in chemical shift artifact which should help narrow the imaging differential. We present a patient with incidental CT and MRI findings which resulted in a prolonged hospital course following misidentification of intraventricular silicone oil. Although the imaging differential for an intraventricular lesion may include metastasis, lymphoma, hemorrhage, choroid plexus papilloma/carcinoma, meningioma, subependymoma, and ependymoma, secondary imaging findings should be noted to ensure an accurate diagnosis. In patients with evidence of prior silicone retinopexy, visualization of an intraventricular lesion with associated chemical shift artifact should raise the possibility of intraventricular silicone oil migration.