Bulky tumors can encroach or touch the cornea. There are no absolute clinical criteria for distinguishing iris nevi from melanoma. Perhaps the two most important clinical features are documented growth and absolute size. These lesions are often vascular and may bleed spontaneously into the anterior chamber. The accuracy of clinical diagnosis of retinoblastoma is high.
Most retinoblastomas have a characteristic clinical appearance.
The presence of calcium within a soft-tissue mass in a child's eye, demonstrated by either computed tomography or ultrasound, is a highly specific sign of retinoblastoma. Retinoblastomas grow beneath the retina, leading to secondary retinal detachment, or grow into the vitreous where they appear as a white tumor mass. The major differential diagnosis of leukocoria is Toxocara endophthalmitis , Coats' disease, retinal dysplasia, persistent hyperplastic primary vitreous, and retinal detachment of unknown cause. The presence of intraocular calcium is an important clinical findings because few simulating lesions in the differential diagnosis become mineralized. Retinocytoma, the benign variant of retinoblastoma, has the appearance of a treated retinoblastoma.