Retinoblastoma

Question 1

What is retinoblastoma?

Answer 1

It is a malignant tumour of the retina, primarily affecting young children which results from a genetic information loss of the tumour suppressor gene(retinoblastoma Rb1)

Question 2

Retinoblastoma is classified on what basis?

Answer 2

• Laterality
• Focality
• Heredity
• Pattern of growth

Question 3

Name the 4 growth patterns of retinoblastoma.

Answer 3

Intraretinal

Endophytic (intravitreal)
» white hazy mass that obscures vessels

Exophytic (subretinal)
» progressive retinal detachment

Diffuse infiltrating pattern (occasionally)
- Simulates uveitis or endophthalmitis

Question 4

Give 4 risk factors for RB.

Answer 4

• Genetic mutation-RB1 gene
  Heritable (40%) or non-heritable (60%)
• Young age
• Family history
• Exposure to radiation

Question 5

How does intraocular RB present? (4)

Answer 5

1. Leukocoria-60%
2. Strabismus-20%
3. Vision loss
4. Redness and swelling; painful

Question 6

How does extraocular RB present? (2)

Answer 6

1. Orbital inflammation
2. Orbital invasion

Question 7

Which signs should probe you to rule out RB?

Answer 7

Leukocoria, strabismus, intraocular inflammation, peri orbital inflammation or glaucoma

Question 8

What is included in the examination of RB? (5)

Answer 8

• Visual acuity - both eyes
• IOP
• Globe enlargement
• RD REFLEX - very important
• Squint/Strabismus
• Hypopyon
• Conjunctival hyperaemia
• Lymphadenopathy
• Fundoscopy if possible

Question 9

Name 3 investigations that should be done in RB.

Answer 9

CT, MRI, B-scan

Question 10

What is the grading for RB?

Answer 10

Group A: Small tumors confined to the retina.

Group B: Larger tumors or those near critical structures.

Group C: Tumors with minimal spread under the retina or into the vitreous.

Group D: Large tumors with widespread seeding and retinal detachment.

Group E: Extensive tumors with poor prognosis for saving the eye.

Question 11

What will you see on histology for RB?

Answer 11

Flexner-Wintersteiner rosettes and fleurettes

Question 12

Give 3 differential diagnosis for RB.

Answer 12

• Coats disease
• Persistent fetal vasculature
  Anterior
  Posterior
• Retinopathy of prematurity
• Uveitis

Question 13

How is Rb treated? (4)

Answer 13

• Photo-coagulation: for small local tumors < 3-4mm
• Radiotherapy
• Cryotherapy:
• Surgical: enucleation, exenteration
• Chemotherapy: to reduce tumor volume
  Vincristine + carboplatin + etoposide (85% Response)

Question 14

Give 3 complications for RB.

Answer 14

1. Metastasis
2. Retinal detachments
3. Glaucoma(closed angle)
4. Secondary malignancies

Question 15

Give 5 differential diagnosis for leukoria.

Answer 15

• retinoblastoma,
• cataracts,
• endogenous endophthalmitis,
• chronic retinal detachment,
• PHPV: persistent hyperplastic primary vitreous,
• Coats’ disease,
• retinopathy of prematurity,
• toxocariasis,
• retinal astrocytoma,
• previous vitreous hemorrhage