A calcified intraocular mass in a child with leukocoria is retinoblastoma until proven otherwise; MRI (not CT) stages optic nerve, choroid and extraocular spread and looks for the pineal tumour of trilateral disease.
Orient first
- The commonest primary intraocular malignancy of childhood; bilateral disease means a germline RB1 mutation.
- Calcification in over 90% on ultrasound; CT is avoided because of radiation sensitivity.
- Mimics: Coats disease (no calcification, subretinal exudate), persistent fetal vasculature.
Acquire the study
- High-frequency ocular probe through closed eyelids with coupling gel; both eyes.
The manoeuvre
- Echogenic intraocular mass with calcific foci and posterior acoustic shadowing.
- Size in mm and position; retinal detachment; vitreous seeding.
- Contralateral eye.
What confirms it
- Calcified intraocular mass on ultrasound in a child with ophthalmoscopic findings; staging on MRI.
What licenses you to exclude it
- A normal ultrasound of both globes excludes a sizeable intraocular mass.
The classic misread
- Ordering CT to show calcification.
- Missing optic nerve invasion by not acquiring thin post-contrast orbital images.