1. Diffuse infiltrating retinoblastoma > >

2. Ocular and General History  5 years old boy  Unremarkable birth history (BBW: 2800g, full-term)  No preceding trauma or ocular history

3. First Presentation  Chief complaint:  Whitish materials in the left eye for 4 days  VA: 20/20 OD, 20/70 OS  IOP: 17mmHg OD, 34mmHg OS  Anterior segment OS:  White iris nodules, pseudohypopyon, large white KPs  Fundus OS:  Snowballs + snowbanking vit. opacity

6. Investigations - Lab  Complete blood count: negative  CRP/ESR: negative  Serology: negative  Syphilis, mycoplasma, toxoplasma, CMV, HSV, EBV  Autoimmune markers: negative  ANA, RF, anti-dsDNA, HLA-B27

7. Investigation - Image  Chest x-ray: normal  B-scan  Presence of vitreous opacity  No mass or calcification  Orbital CT scan  Fusiform soft tissue density at inferior region of globe  No calcification

10. Probable differential diagnosis  Granulomatous panuveitis OS, complicated with IOP elevation  nature?

11. Treatment  Empirical treatment  Topical steroid (prednisolone acetate 1% oph susp QID)  Antiglaucoma medication (dorzolamide 2% oph susp BID)  Long-acting cycloplegics (atropine 0.5% eye drops BID)

12. Second presentation: 4 weeks later  Persistant elevation in IOP: 37mmHg OS  Increase in pseudohypopyon  Mild decrease in iris nodules and keratic precipitates

14. Revised differential diagnosis  Masquerade syndrome, retinoblastoma highly suspected

15. Consequences  Direct enucleation of left eye without fine needle aspiration biopsy  Histopathological diagnosis:  poorly differentiated retinoblastoma with tumor invasion involving retina, choroid, sclera, ciliary body, trabecular meshwork, iris, corneal endothelium

16. HE stain, 400X

17. HE stain, 40X HE stain, 100X sclera TM Ciliary body irisiris lens Corneal endothelium Optic nerve

18. Final Diagnosis  Diffuse infiltrating retinoblastoma OS  An atypical presentation of retinoblastoma  Lack of discrete retinal mass or calcification  Extensive seeding of tumor cells into vitreous and anterior chamber producing an inflammatory appearance mimicking uveitis  Patient presented at an older age than the typical retinoblastoma patients

19. Conclusion  Retinoblastoma can present in a diffuse infiltrating pattern in rare cases  Keep this differential diagnosis when encountering pediatric patients presenting with an atypical uveitis