Most common intraocular tumour of childhood is:

Ans: b (Retinoblastoma) Ref: AK Khurana, 4th ed, p. 280 * Retinoblastoma is the most common intraocular tumour occurring in 1 in 20000 live births * Arises from the neurosensory layer of retinalneuroectodermal) * Sporadic 94% Familial 6% * Bilateral 30-40% Unilateral 60-70% *Heritable 40% (All familial + l/3rd of sporadic) Nonheritable 60% - Rb gene is a tumour suppressor gene on Ch 13 long arm. Loss or inactivation of both the normal allele lead to Rb. - Histopathology: - Flexner wintersteiner rosettes (highly specific) - Homer wright rosettes - Pseudorosettes - Necrosis & calcification C/F:- 1. Leukocoria (Amaurotic cats eye reflex)- M.C. manifestation 2. Squint(2nd MC) 3. Secondary glaucoma 4. Nystagmus Inv: A. On Ophthalmoscopy 2 appearances 1. Endophytic retinoblastoma with calcification- Cottage cheese appearance 2. Exophytic Rb with appearance of exudative retinal detachment B. USG C. CT Scan Both detects calcification D. MRI - to study optic nerve & sellar & parasellar regions of brain Treatment: Small tumours (<4 mm diameter < 2 mm thickness) 1. Laser photocoagulation 2. cryotherapy (anterior to equator) 3. transpupillary thermotherapy Medium sized tumours (< 12 mm dia < 6 mm thickness) 1. Brachyterapy using episcleral plaque applicator 2. Chemoreduction - agents vincristine, carboplatin & etoposide Large tumours 1. Enucleation 2. Chemoreduction Extracranial ext. -- external beam radiotherapy Recurrent/ metastasis-- chemotherapy Prognosis: Reese Elsworth system Indications of enucleation 1. No chance of preserving useful vision 2. Tumour involving half of globe 3. Optic nerve involvement 4. Glaucoma or AC involvement 5. Gross vitreous seedings