Retinoblastoma Flashcards
most common intraocular malignant tumor of childhood?
RB
% bilaterality of RB?
30-40%
genetic defect in RB?
mutation in RB1 tumor supressor gene located on long arm of chromosome 13. BOTH copies must be mutated for tumor to develop
most common presenting signs of RB for patients younger than 5?
leukocoria (60%), followed by strabismus (20%) and ocular inflammation (5%)
patient with bilateral retinoblastoma. what is the likelihood their child will have RB assuming spouse is unaffected
45% (and of these, 85% will be bilateral: Extremely high likelihood that this patient has a germline mutation, meaning 50% chance of passing on abnormal gene, and 90% penetrance. That means that 90% of the time, the other, previously normal RB gene will mutate (need two mutations for tumor development)
chance of your offspring getting RB when you have unilateral RB?
7-15% (of these, 85% will be bilateral)
If parents are unaffected, what is that chance that a child with RB will have bilateral disease?
33%
Normal parents of a child with bilateral involvement. Chance of sibling having RB?
5%
Most common presenting signs in RD for patients 5 and older?
Leukocoria (35%), decreased vision (35%), and strabismus (15%)
Appearance of retinal vessels in RB compared to Coats?
normal in RB
what type of RB tumors are more apt to causing vitreous seeds?
endophytic
most common sites for RB mets?
Skull bones, distal bones, brain, spinal cord, lymph nodes. Generally spread by direct extension into optic nerve or through sclera.
small, smooth, white, glistening tumor of retina, in some cases larger and calcified with a mulberry appearance
retinal astrocytoma
What does the Reese-Ellsworth classification of RB predict?
eye survival (not vision, and not patient survival)
What factors are considered in the International Classification System for Response to Chemotherapy?
size, subretinal fluid, vitreous seeding
(and the following are considered as features as an unsalvageable eye: tumor in ciliary body or anterior segment, neovasc glaucoma, vit heme, phthisis, orbital-cellulitis-like presentation)
what test(s) should be ordered in all patients diagnosed with RB?
MRI brain with and w/o contrast (to rule out intracranial involvement)
what additional tissue is affected in trilateral retinoblastoma?
pineal gland
Four most important prognostic features of RB?
extraocular extension (most important), optic nerve involvement, choroidal invasion > 3mm (up for debate), trilateral involvement
In the Western world, what is the survival rate of RB contained in the eye? With extraocular spread?
95%
less than 50%
most common second malignancies in RB patients outside the field of radiation?
osteosarcoma, fibrosarcoma, soft tissue sarcoma
most common second malignancies in RB patients inside the field of radiation?
osteosarcoma, melanoma, pinealoma, Ewing sarcoma, papillary thyroid carcinoma
ultrasound finding in RB to differentiate from other causes of leukocoria?
focal areas of high reflectivity (from calcium, which is much more common in RB than other causes of leukocoria)
