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What is Which of the following is commonest primary intraocular tumour in childhood is and explain in detail?
(Retinoblastoma): Ref: 280-KH, 358-K, 397-PRETINOBLASTOMA - is the most common primary intraocular malignancy of childhood.* The retinoblastoma may be heritable (40%) or non heritable (60%)* The predisposing gene (RPE1) is at 13q14* Leukocoria (white papillary reflex) is the commonest (60%) presentation* Delation involving the long arm of chromosomes 22 (22ql 1) are most common microdeletions identified to date, VCF (Velo Cardio Facial) syndrome is the most common associated syndromeTreatments1. Small tumour - no more than 4 mm diameter and 2 mm thickness without vitreous or subretinal seeds - Trans papillary thermotherapy laser or cryotherapy2. Median size tumour(I) Brachytherapy - is indicated for tumours of no more than 12 mm diameter and 6 mm thickness (60Co or I125)(II) Chemotherapy - (Carboplatin, vincristine, etoposide) may be combined with cyclosporin(III) External beam radiotherapy - should be avoided, because high risk of complications, cataract formation, radiation retinopathy and cosmetic deformity and secondary malignancy.3. Large tumours (a) Chemotherapy (b) Enucleation4. Extra ocular extension - beyond the lamina cribosa is treated with chemotherapy after enucleation* Extension to the cut end of the optic nerve or extension through the sclera - chemotherapy and irradiation of the affected orbit5. Metastatic disease: - High dose chemotherapy Enucleation is the treatment of choice when the child is brought in clinical stage II or late stage I (when tumour is more than 100 mm in size or when optic nerve is involved) (270-KH)