Calcified scleral choristoma in organoid nevus syndrome simulating retinoblastoma.

A child referred for management of retinoblastoma who alternatively had a calcified scleral choristoma as part of previously undiagnosed organoid nevus syndrome is described. A 31-month-old male infant with scalp alopecia was referred for retinoblastoma management after a calcified mass in his left eye was found. Ophthalmic examination revealed the mass was of choroidal or scleral origin, underlying the retina. The amelanotic circumpapillary mass extended superonasally in a geographic configuration and measured 14×12 mm. There was no subretinal fluid, hemorrhage, feeder vessels, or tumor seeding. Ocular ultrasonography confirmed a homogeneous calcified intraocular mass 3.1 mm in thickness. Enhanced depth imaging optical coherence tomography revealed that the lesion was located within the sclera compressing the overlying choroidal tissue. Further evaluation disclosed cutaneous aplasia cutis congenita with nevus sebaceous of Jadassohn. Magnetic resonance imaging disclosed an arachnoid cyst of the brain. Later, optical coherence tomography revealed the mass to be in the deep choroid or within the sclera. This constellation of ocular, cutaneous, and neurological features were suggestive of organoid nevus syndrome. At the 2-year follow-up, the findings were stable. The calcified choristoma of organoid nevus syndrome, located within the sclera in this case, has distinctive clinical features that differentiate this benign tumor from retinoblastoma.