Approach to abnormal red light reflex (retinoblastoma)

Question 1

how do we get a normal red light reflex?

Answer 1

light is reflected back out through the transparent optical media from the inner back of the eye

Question 2

what does it mean when there is an abnormal red light reflex?

Answer 2

there would be asymmetry in the red light reflex, or there could be leukokoria (white reflex)

Question 3

what ddx should be considered with asymmetrical red light reflex?

Answer 3

• coloboma
• no iris
• refractive errors ➔ myopia, hyperopia, astigmatism
• dilating drops
• trauma

Question 4

what ddx should be considered with leukokoria?

Answer 4

• retinoblastoma
• pediatric cataracts
• glaucoma
• retinopathy of prematurity
• retinal detachment
• posterior coloboma

Question 5

what is retinoblastoma?

Answer 5

pediatric (<5Y) eye cancer – specifically of the retina

Question 6

what are the types of RB?

Answer 6

hereditary and sporadic

Question 7

tell me about hereditary RB

Answer 7

AD inheritance from parent, AR penetrance – requires additional mutation to occur to present with disease

usually presents earlier in life with multifocal disease in both eyes

is predisposed to other cancers and with radiation exposure has an even higher risk of dev new primary cancer

Question 8

tell me about sporadic RB

Answer 8

usually presents later (~3Y), with unilateral and solitary and somatic mass

less of a chance of new primary in future

2 hit hypothesis for development

Question 9

what are common spots of mets for RB?

Answer 9

brain, bones, lungs, and liver

Question 10

how do we screen for RB?

Answer 10

in all pediatric appointments, red light reflex is usually done as a part of standard of care

Question 11

how might someone with RB present?

Answer 11

• leukocoria
• strabismus
• painful red eye
• secondary glaucoma
• orbital inflammation/cellulitis
• decrease vision

unilateral or bilateral

Question 12

what hx information do you want to know in someone with leukocoria?

Answer 12

FHx of cancers, retinoblastoma, and ocular disorders

recent trauma

pediatric follow-up information (reg visits with a pediatrician)

Question 13

what P/Es would you want to do with someone with leukocoria?

Answer 13

1. fundoscopy if not done already
2. LN exam in head and neck region

Question 14

what diagnostic tests would you order? how about non-diagnostic?

Answer 14

diagnostic
1. examination under anesthesia ➔ fundus photos and u/s
2. fundoscopy

other
1. MRI - search for brain mets – no CT bc increase chance of dev another primary later in life esp in hereditary
2. bone scan / bone marrow aspiration- bone mets
3. genetic testing - trio analysis for RB variant in mom and dad
4. lumbar puncture for CSF analysis

Question 15

how do you treat RB?

Answer 15

1. refer/consult ped oncology, genetics, ophthalmology
2. focal therapies – esp if RB is confined to the eye
   - intraocular chemo (intravitreal or intra-arterial) ➔ alkylating agent, vinca alkaloid, or topoisomerase II inhibitor
   - brachytherapy – radioactive plaques
   - cryotherapy
   - laser photocoagulation
3. high risk could consider systemic chemotherapy combinations or enucleation