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Child presents with an eye full of blood. On examination, the eye has low pressure, dislocated lens, and abnormal ciliary muscle.
Retinoblastoma is the most common primary intraocular malignancy of childhood. The tumour is of neuronal origin and results from the loss or inactivation of both alleles of the RB gene. Patients with germline RB mutations may present with bilateral retinoblastomas or “trilateral” retinoblastoma (associated with pineoblastoma).
Microscopically, retinoblastomas are a small round blue cell tumour and may show varying degrees of differentiation. Differentiated areas demonstrate characteristic Flexner-Wintersteiner rosettes (tumour cells surrounding a central lumen) and Homer Wright rosettes (tumour cells surrounding a less defined lumen). In this case, extensive hemorrhage and necrosis is associated with a poorly differentiated tumour. Invasion of the optic nerve, choroidal invasion, and/or extra-ocular extension are poor prognostic features and are all present in this case.