Retinoblastoma

Question 1

Define retinoblastoma

Answer 1

Malignant intraocular tumour of the retinal cells often seen in children

Question 2

What is the aetiology for retinoblastoma

Answer 2

Mutation in both alleles of the tumour suppressor RB1 gene (double hit) on chromosome 13, other mutations are present for progression to clinical retinoblastoma
- familial RB (retinoblastoma) - child born with one RB mutation (hit 1) - Acquire second somatic mutation (hit 2) -bilateral disease + family history
Or
- Sporadic RB - Acquire one somatic mutation (hit 1) - Then second somatic mutation in same cell (hit 2) - unilateral disease

Question 3

What are the risk factors for retinoblastoma

Answer 3

<3 years old (90%)
Family history (10%)
HPV infection
Advanced paternal age

Question 4

What are the symptoms of retinoblastoma

Answer 4

Usually <3 yo

“chalky eye” (White haze, Asymmetrical (sporadic disease))
Pseudo-orbital cellulitis
Visual disturbance (bilateral or due to glaucoma)
Ocular pain

Question 5

What are the differentials for retinoblastoma

Answer 5

Coat’s disease (exudative retinitis or retinal telangiectasis)
Retinopathy of prematurity
Ocular toxocariasis
Astrocytic hamartoma
Medullo-epithelioma
Congenital cataracts

Question 6

What are the signs of retinoblastoma on examination

Answer 6

Eyes
- Leukocoria (White pupillary reflex (red reflex not visible))
- Strabismus
- Pseudo-orbital cellulitis

Question 7

What are the investigations for retinoblastoma

Answer 7

Bedside: fundoscopy: Chalky, white-grey retinal mass; may show retinal detachment with retinal vessels visible behind the lens; may show vitreous and/or subretinal seeding

Bloods: genetic testing: RB1 mutation

Other:
- sdOCT
- Ultrasound
- MRI head/orbit
- bone marrow aspiration (mets)
- LP (mets)

Question 8

What is the management for retinoblastoma

Answer 8

Anterior chamber involvement/glaucoma/inflammation → enucleation (removal of eye) + chemotherapy (bilateral)

Vitreous seeding: chemotherapy

No vitreous seeding: chemotherapy OR laser ablation

Question 9

What are the complications of retinoblastoma

Answer 9

Secondary malignancy e.g. lymphoma, leukaemia (especially after chemo or radiotherapy)

Question 10

What is the prognosis for retinoblastoma

Answer 10

Most cured, some may be visually impaired (>90% survive to childhood)
Risk of secondary malignancy (sarcoma) in survivors of hereditary retinoblastoma