Review Question - QID 221295

This otherwise healthy patient presents with leukocoria, which is seen as a white pupillary reflex. This finding requires an urgent referral to ophthalmology for further evaluation due to the risk of retinoblastoma in these children.

Retinoblastoma is the most common intraocular cancer of childhood. This disease is caused by mutations in the RB1 tumor suppressor gene that encodes the retinoblastoma protein. Retinoblastoma typically presents as leukocoria in a child under the age of 3 with other signs, including strabismus, nystagmus, or a red, inflamed eye. The differential diagnosis for leukocoria includes retinoblastoma, cataract, vitreous hemorrhage, retinal detachment, and other intraocular/systemic disease processes. Treatment options include chemotherapy, laser photocoagulation, radiation, cryotherapy, and enucleation. Prompt diagnosis and treatment are important for optimal visual outcome and survival.

Francis et al. studied the risk of extraocular extension in eyes with retinoblastoma that received intravitreous chemotherapy injections. They discuss how the risk of extraocular extension is small. They recommend the regular use of precautionary injection methods, such as lowering of intraocular pressure, cryotherapy, ocular surface irrigation, and ultrasonic biomicroscopy surveillance of the injection site.

Figure/Illustration A is a clinical photograph that demonstrates leukocoria in the eye (red circle). This finding is consistent with a diagnosis of retinoblastoma.

Incorrect Answers:
Answer 1: Biopsy is typically used to make a diagnosis of tumor; however, biopsy of the eye is contraindicated in retinoblastoma due to the risk of tumor seeding. Instead, treatment is with enucleation in order to remove the source of the disease.

Answer 2: Genetic testing can be used to determine if a patient has the hereditary form of retinoblastoma, characterized by germline RB1 mutations, as opposed to the nonheritable form, which is associated with somatic RB1 mutations. An ophthalmological evaluation is required first to confirm the diagnosis.

Answer 3: While magnetic resonance imaging of the brain and orbits should be performed in all children with suspected retinoblastoma to assess disease extent, an ophthalmological evaluation should be completed first.

Answer 5: Reassurance or reevaluation at the next well-child visit is not appropriate management of newly diagnosed leukocoria, given that undiagnosed retinoblastoma can be vision- and life-threatening.

Bullet Summary:
The finding of leukocoria in a child requires urgent ophthalmologic referral to rule out retinoblastoma.