pediatrics
Retinoblastoma
Diagnosis of Retinoblastoma
Orbital ultrasonography, CT, or MRI Sometimes optical coherence tomography, bone scan, bone marrow aspirate and biopsy, and lumbar puncture When the diagnosis is suspected, both fundi must be closely examined by indirect ophthalmoscopy with the pupils widely dilated and the child under general anesthesia. The cancers appear as single or multiple gray-white elevations in the retina; cancer seeds may be visible in the vitreous. Diagnosis of retinoblastoma is usually confirmed by orbital ultrasonography, MRI, or CT. In almost all cancers, calcification can be detected by CT. However, if the optic nerve appears abnormal during ophthalmoscopy, orbital MRI is better for finding cancer extension into the optic nerve or choroid. Optical coherence tomography, a noninvasive imaging test, is sometimes used. If optic nerve extension is suspected or extensive choroidal invasion is present, a lumbar puncture and brain MRI should be done to assess for metastasis. Because distant metastasis is rare, bone marrow evaluation and bone scan can be reserved for patients with bony symptoms or for those with clear evidence of metastatic disease. Because of the risk of tumor spread, there is no clear role for ocular tumor biopsy to obtain a tissue diagnosis. Patients with retinoblastoma require molecular genetic testing, and if a germline mutation is identified, parents should also be tested for the same mutation. If subsequent offspring of parents have the germline mutation, the same genetic testing and regular ophthalmologic examination are required. Recombinant DNA probes may be useful for detecting asymptomatic carriers. Children who have aparent or sibling with a history of retinoblastomashould be evaluated by an ophthalmologist shortly after birth and then every 4 months until age 4 years. 