A 1.5-year-old boy with leucocoria was referred to our clinic for a cystic structure with very well-defined borders filling the left eyeball, which was obvious both in ultrasonography and MRI. A limbal lensectomy and vitrectomy was performed. The cyst was under the retina, and the base was attached strongly to the nasal choroid. The cyst fluid was first aspirated with a 41-gauge cannula to make the cyst smaller, and it was dissected from the overlying retina and underlying choroid from the attachment site in the nasal quadrant; it could be extracted as a whole without damaging the cyst wall from a limbal incision with the help of a cryo probe. The retina was attached, lasered and tamponaded with silicone oil. It stayed attached after removal of the silicone oil, and the child has ambulatory vision with that eye.