Intraocular Tumours Flashcards
Describe inheritance of retinoblastoma (when not spontaneous).
Transmitted via a gene on chromosome 13 as an autosomal dominant trait with 80% penetrance.
Approximately 6% of patients have a family history.
In sporadic cases, 25% involve a new germline mutation which is, therefore, transmissible to offspring. Screening of siblings and offspring is vital.
What is the most common primary intraocular malignancy in children, and what age do they normally present at?
Retinoblastoma.
Frequency usually 1 in 20,000.
Presentation usually at age of about 18 months.
What are the 7 causes of leukocoria?
- Cataract
- Toxocara granuloma
- Advanced retinopathy of prematurity
- Vitreous maldevelopment (persistent hyperplastic primary vitreous)
- Retinal dysplasia
- Corneal opacity
- Retinoblastoma
How does the retinoblastoma look?
Usually appears as a whitish fleshy mass, which may be extremely large at presentation. Alternatively, it may grow beneath and elevate the retina.
Strabismus and secondary glaucoma may occur.
Investigation for retinoblastoma should confirm the diagnosis, and establish the presence of what?
Establish the presence and extent of extraocular spread, which may occur by local invasion and by haematogenous and lymphatic dissemination.
What investigation means are used in diagnosis of retinoblastoma?
US, CT and MRI of the globe and orbit demonstrate the tumour and may show characteristic calcification.
Serology may exclude a toxocara granuloma.
Blood tests for a variety of tumour markers are sometimes positive.
Systemic assessment for metastasis includes imaging, lumbar puncture, and bone marrow aspiration.
Management of retinoblastoma?
Large tumours are treated by removal of the eye (enucleation).
Radiotherapy and chemotherapy are useful in some circumstances, often as an adjunct to enucleation.
Prognosis of retinoblastoma?
The extent of optic nerve invasion will determine prognosis.
A tumour confined to the globe is associated with a survival rate of over 90% at 3 years.
Invasion beyond the neural transection point, however, carries a poor prognosis.
A secondary primary malignancy, such as a peripheral sarcoma, will develop in 10% or so of patients.
What is a choroidal naevus?
A grey-brown flat or slightly raised discrete oval area. Most are less than three disc diameters across. Very common, found in as many as 10% of general population.
Small danger of malignant change, so suspicious lesions should be examined periodically.
Where do uveal melanomas occur most?
80% are choroidal. The remainder develop in the iris (5%) or the ciliary body (15%)
What is the most common primary intraocular malignancy to affect adults, and with an average age of what at presentation?
Choroidal melanoma.
Average age of 50 at presentation.
What are 5 clinical features suggestive of malignancy (eg. when considering choroidal naevus vs melanoma)?
- Flashing lights (photopsia)
- Substantial elevation (of lesion)
- Adjacent exudative retinal detachment
- Presence of orange pigment deposits
- Increasing size of lesion
What is the most useful imaging technique for choroidal melanoma?
Ocular US most useful: aids in diagnosis, assessment of tumour size and in the detection of transsceral extension.
Management of choroidal melanomas?
Controversial and individual.
Eyes with very large tumours usually require enucleation.
In certain pts, treatments to preserve the globe are used: proton beam radiotherapy, radio-active plaque application and local resection.
When distant spread has occurred, palliative chemotherapy.
Prognosis of choroidal melanomas?
Quite variable. Depends primarily upon tumour size (particularly thickness), histological cell type and the presence or absence of detectable systemic metastasis.
