Magnetic resonance features in advanced retinoblastoma - what a paediatric radiologist needs to know.

Retinoblastoma is the most common intra-ocular malignancy in children worldwide. Current treatment modalities include focal therapy such as laser or cryotherapy, intravenous chemotherapy, intra-arterial chemotherapy and surgical enucleation. According to the current retinoblastoma staging systems, there are a few common features indicating advanced disease stage, which can subsequently predict the prognosis and the necessity of surgical enucleation and adjuvant chemotherapy. This review uses annotated magnetic resonance (MR) images to illustrate these features, which include (1) retinal detachment, (2) vitreous and subretinal seeding, (3) choroidal invasion, (4) anterior segment invasion and increase in intra-ocular pressure, (5) iris neovascularization, (6) vitreous haemorrhage, (7) aseptic orbital cellulitis with lens dislocation, (8) post-laminar optic nerve invasion and (9) distant and systemic metastasis. Prompt identification of these features is important for paediatric radiologists to guide the clinical team for appropriate management.