Retinoblastoma

Epidemiology
300 cases/year
Almost all patients are under 5
60 - 70% sporadic
30 - 40% hereditary (younger patients, more likely to be bilateral, 5 - 10% develop osteosarcoma later in life)

Trilateral RB (Bilateral RB with pineal PNET)
5 to 10% of hereditary RB cases

Biology
Two-hit hypothesis
Rb is tumor suppressor gene located on chromosome 13
If a mutated copy of Rb is inherited, patients are at higher risk of losing the second copy and developing RB

Clinical
Leukocoria, strabismus, decreased visual acuity
Biopsy is contraindicated as it can seed the rest of the eye

Treatment
Primarily laser/surgical
Plaque brachy can be performed