Snapshot A 2-year-old boy presents to his pediatrician for strabismus. Family history is notable for osteosarcoma in his father. Physical examination is notable for strabismus and bilateral leukocoria. He is referred to a pediatric ophthalmologist for further evaluation. Introduction Overview a primary intraocular malignancy arising from the retina login to view 7 more bullets Epidemiology Incidence most commonly affects children (< 5 years of age) ETIOLOGY Pathophysiology RB1 gene encodes a nuclear protein, retinoblastoma, that serves as a tumor suppressor login to view 3 more bullets loss of the RB1 gene dysregulates the cell cycle and results abnormal cellular proliferation "2-hit hypothesis" login to view 3 more bullets Associated conditions osteosarcoma Presentation Symptoms visual loss Physical exam leukocoria loss of/abnormal red reflex strabismus nystagmus Imaging Ocular ultrasonography indication login to view 2 more bullets Optical coherence tomography indication login to view 2 more bullets MRI Brain and orbit indication login to view 2 more bullets Studies Ophthalmic evaluation under anesthesia indication login to view 2 more bullets findings login to view 2 more bullets Biopsy contraindicated because of the risk of tumor seeding Genetic testing performed in all cases Differential Cataract differentiating factor login to view 1 more bullet Treatment Medical local and systemic chemotherapy login to view 2 more bullets Surgical laser photoablation login to view 2 more bullets radioactive plaques login to view 2 more bullets cryotherapy login to view 2 more bullets enucleation login to view 2 more bullets Complications Metastatic disease Blindness Prognosis Deadly if not treated the tumor expands to fill the eye and destroy the globe > 95% survival with treatment