Retinoblastoma: Atypical Presentation & Simulators Dr. Njambi Ombaba; Paediatric Ophthalmologist, University of Nairobi Objectives • To review of typical presentation of retinoblastoma • To understand the atypical presentation • To understand the Rb simulators Presentation of retinoblastoma Growth patterns Endophytic: Inner retina, vitreous mass, no overlying vessels, pseudohypopyon Exophytic: Outer retina, SR space mass, overlying vessels, RD Diffuse: No mass, signs of inflammation/ endophthalmitis Echogenic soft tissue mass Variable shadowing – calcification Persistent on reduced gain Heterogeneous – necrosis/ haemorrhage Floating debris- vitreous seeds, increased globulin MRI- • Pre-treatment staging T1- Hyper intense to vitreous T2-Hypo intense to vitreous T1:C+Gd- homo/ heterogeneous Enhancement: Choroid & AC ON involvement Hypo intense sclera- Normal Trilateral retinoblastoma CT SCAN Typically a mass of high density Usually calcified and moderately enhancing on iodinated contrast CT has a sensitivity of 81–96%, and a higher specificity for calcification detection However, delineation of intraocular soft-tissue detail is limited. Low sensitivity for ON invasion Atypical presentation Non calcified Retinoblastoma Calcification is key to diagnosis retinoblastoma US detects calcifications in 92–95% of positive cases Non-calcified retinoblastomas: 1. Tumefaction with irregular internal structure 2. Medium reflectivity 3. Typical signs of vascularity 4. Retinal detachment with part of the retinal surface destroyed. Rare, 2% of all RB cases Mean age 6 years Seeding in vitreous and anterior chamber Pseudouveitis, Pseudohypopyon No mass on Fundoscopy BUT Placoid thickening of retina Uveitis masquerade syndrome Diagnosis likely to be missed Retinoblastoma in adulthood • Extremely rare • Histology : PT1a • 33 year old at KNH • Poor vision • Vitreous heme of unknown aetiology • PPV for examination • Small mass, growth over time • FNA consistent with RB Calcified Simulators Optic nerve head drusen Bilateral Calcified hyaline bodies Pseudopapilloedema Buried in children Increased reflectivity deep in the optic Optic nerve drusen Maximize detection of reflected ultrasound waves, angulate the probe so as to avoid the lens Retinal astrocytoma Hermatoma Tuberous sclerosis Slowly growing Older children Medulloepethelioma/ Diktyoma • Rare tumour arising from ciliary body • Primitive medullary epithelium • Teratoneuroma Neural tube strands Diktyoma • 2 year old • Leukocoria • EUA: Not typical RB • Traumatic cataract and Uveitis • Later developed total hyphaema • Enucleation Non calcified simulators Persistent hyperplastic primary vitreous (PHPV) Almost always unilateral Microphthalmos Dense retrolental mass +/- vascular Prominent ciliary processes Rare association with RB Persistent hyperplastic primary vitreous (PHPV) No calcification on ultrasound or CT scan. Coat’s disease Almost always unilateral Boys Loss of vision Yellowish leukocoria Exudative detachment Telangiectasia vessels Subretinal lipid and cholesterol crystals Coat’s disease No definite mass Diffuse increase in vitreous opacity Intraocular calcification rare Exudative RD Endogenous endophthalmitis Haematogenous spread from distant loci Meningitis, endocarditis, sepsis Staphylococcus, Streptococcus , Meningococcus commonest organisms Systemic infection; Sick child Marked vitreous opacification Endogenous endophthalmitis Ocular Toxocariasis Chronic endophthalmitis with opaque vitreous Solitary retinal granuloma Healthy child , contact with dogs/ cats Marked vitreous inflammation; yellow- grey strands from lesion to vitreous Serological test supportive No Calcification Retinal dysplasia Congenital , Bilateral Roving eyes + Leukocoria Boys Isolated / Syndromic Norrie’s disease, Warburg Incontinentia pigmenti Trisomy 13,8 Retinal detachment Coloboma Retinoblastoma-related cataract Rare, less than 1% occurrence TGF-β produced by retinoblastoma cells may induce cataract formation Take home message Diagnosis of retinoblastoma is straight forward in most cases High index of suspicion In doubtful situations; choose life .