Retinoblastoma

TM is a 2-year-old child who had been examined by her local ophthalmologist and suspected to have an intraocular tumor on indirect ophthalmoscopy. She was referred to a pediatric ophthalmologist for an examination under anesthesia and echography. Ultrasound was performed through closed lids and the initial impression was that of a small irregularly reflective lesion that was in the extreme inferior periphery near the ciliary body. The differential diagnosis included a dyktioma (medulloepithelioma) because of this apparently anterior location. Indirect ophthalmoscopy using a cotton tip applicator to rotate the globe was then performed and the lesion was seen to be just inferior to the equator. This immediately made the diagnosis of dyktioma untenable and retinoblastoma much more likely. The child had a marked Bell’s phenomenon while asleep and the eye had rotated superiorly, which rotated the lesion quite inferiorly, resulting in the erroneous localization by echography (Fig. 45).