retinoblastoma Flashcards
What is Retinoblastoma?
The most common primary intraocular malignancy of childhood, arising from primitive retinal cells.
What is the incidence of Retinoblastoma?
1 in 17,000 live births, accounting for about 3% of all childhood cancers.
Is there a gender or racial predisposition for Retinoblastoma?
No, there is no sexual or racial predisposition.
What is the mean age of diagnosis for Retinoblastoma?
4 months (known history), 12 months (bilateral cases), 24 months (unilateral cases), 90% of cases occur before 3 years of age.
What is Trilateral Retinoblastoma?
Bilateral RB with ectopic intracranial RB, usually in the pineal gland or parasellar region.
What percentage of Retinoblastoma cases are unilateral?
60-70% of cases are unilateral.
What percentage of Retinoblastoma cases are bilateral?
30-40% of cases are bilateral.
How does Retinoblastoma inherit?
It is mostly sporadic, but familial transmission follows autosomal dominant inheritance.
What are the routes of spread of Retinoblastoma?
Direct tumor infiltration, subarachnoid space of optic nerve, anterior spread, lymphatic dissemination, hematogenous dissemination.
What is the most common clinical manifestation of Retinoblastoma?
Leucocoria (white pupillary reflex), occurring in 56% of cases.
What are other clinical manifestations of Retinoblastoma?
Strabismus (20%), red painful eye (7%), poor vision (5%), orbital cellulitis (3%), unilateral mydriasis (2%), heterochromia irididis (1%), hyphema (1%).
What are the patterns of growth for Retinoblastoma?
Endophytic, Exophytic, Mixed, and Diffuse Infiltrating.
Describe the Endophytic growth pattern of Retinoblastoma.
Arises from inner retinal layers, fills the vitreous cavity, may spread via aqueous venous channels and lymphatics, causes visual disturbance and white eye reflex.
Describe the Exophytic growth pattern of Retinoblastoma.
Arises from outer retinal layers, fills the subretinal space, leads to serous retinal detachment, can cause proptosis and retinal detachment.
What is the most common growth pattern of Retinoblastoma?
Mixed growth pattern.
What is the Diffuse Infiltrating growth pattern of Retinoblastoma?
No mass formation, signs of endophthalmitis, average age of diagnosis is 6 years, often unilateral and sporadic, diagnosis is delayed and difficult.
What are the four clinical stages of Retinoblastoma?
Quiescent stage, Glaucomatous stage, Stage of extraocular extension, Stage of distant metastasis.
What happens in the Quiescent stage of Retinoblastoma?
Lasts 6 months to 1 year; presents with leukocoria, squint, rare nystagmus, and defective vision in late cases.
What happens in the Glaucomatous stage of Retinoblastoma?
Severe pain, redness, watering, enlarged eyeball, conjunctival congestion, hazy cornea, increased intraocular pressure.
What happens in the Stage of Extraocular Extension of Retinoblastoma?
Tumor enlarges, breaks through the sclera, leading to proptosis and involvement of extraocular tissues.
What happens in the Stage of Distant Metastasis of Retinoblastoma?
Lymphatic spread to preauricular and neighboring lymph nodes, direct extension to the optic nerve and brain, hematogenous spread to bones and liver.
What is the International Classification of Retinoblastoma (ICRB)?
A classification system dividing tumors into Groups A-E based on size and spread.
Describe Group A Retinoblastoma in the ICRB classification.
Small intraretinal tumors (<3mm) away from the foveola and optic disc.
Describe Group B Retinoblastoma in the ICRB classification.
Tumors >3mm, macular or juxtapapillary location, or with subretinal fluid.
