Migration of intraocular silicone oil, used in the treatment of complicated retinal detachment, has been rarely described, but when it happens it can arise with a differential diagnosis with scleral buckling extrusion, tumor, dermoid, ocular cysticercosis, and abscess. The presence of silicone oil in the eye gives very ugly echographic pictures, but these kinds of pictures can be very useful in making a differential diagnosis in the above-mentioned cases. A 39-year-old white female complained of the presence of conjunctival hyperemia and tearing in the right eye (RE); her visual acuity was hand motion, and the intraocular pressure was 14 mmHg. In the upper nasal quadrant a dome shaped lesion was detected. Due to the lens opacities, the patient underwent an echographic examination, which revealed the presence of silicon oil both in the vitreous chamber and in a large subconjunctival space, corresponding to the lesion. This article in addition provides a possible explanation of such cystic formation and discusses the risk factors and the role of the echographic examination in such cases.