Tumours

Tumours

·        Can occur on the iris, ciliary body, choroids

Malignant Melanoma of the Choroid

·        Presentation: elderly, usually white, visual loss from retinal detachment or incidental

·        Retinal appearance: light to darkly pigmented ovoid, elevated mass.  Many variants

·        2^nd most common site of melanoma after the skin

·        Prognosis depends on cell type (Spindle A, Spindle B, Epithelioid or Mixed) and Stage. Overall 50% at 15 years

Retinoblastoma

·        Life threatening

·        1:20,000 live births.  First few years of life

·        Types:

o  60% sporadic

o  40% familial (90% bilateral and/or multifocal)

·        Presentation: strabismus (squint), „white‟ patches on papillary/red reflex (leukocoria), red eye

·        Pathogenesis:

o  Due to variety of mutations in the tumour suppressor gene RB1 at 13q14 – inactivated a protein which down regulates cell growth

o  Need both alleles to be mutated to cause cancer. Hereditary neuroblastoma = inherit one defective gene from parent, with other allele in one cell undergoing spontaneous mutation. If non-hereditary, need to acquire mutations to both alleles in one cell

·        Gross appearance: flat, elevated, diffuse, multicentric pale tumour nodules of plaques

·        Microscopic appearance: small round cells with hyperchromatic nuclei, rosettes are characteristic, areas of necrosis and calcification

·        Treatment: remove eye

·        Complications:

o  Metastasis eg in CNS.  From occurrence in eye to spreading down the optic track is ~ 6 months 

o  Survivors have a 20% chance of developing malignant tumours at 10 years: osteosarcoma or rhabdomyosarcoma

·        Prognosis: 90% 5-year survival (less if optic nerve invasion).