Description, Signs, Incidence, Significance, See Also
See RETINOBLASTOMA AND LEUKOCORIA – assessment
Various imaging tests (including B-scan ultrasound, computed tomography, magnetic resonance imaging and fluorescein angiography) are used to exclude differential diagnoses, detect calcification, measure tumor dimensions and delineate extraocular extension or metastases. They are also required to visualize lesions obscured by vitreous opacification or retinal detachment.
Further tests are required when the diagnosis is equivocal. For example, ELISA (enzyme linked immunosorbent assay) is useful in the diagnosis of ocular toxocariasis. Anterior chamber paracentesis and/or fine-needle aspiration biopsy are occasionally performed, but carry the risk of facilitating dissemination of retinoblastoma. In some cases of advanced or metastatic retinoblastoma, further investigations including lumbar puncture, bone marrow aspiration and tumor markers are indicated.
Laser and incisional surgery
The management of retinoblastoma is complex. In many cases, radioactive plaques are sutured to the sclera adjacent to the tumor (brachytherapy). Tumors less than 3mm in greatest diameter, without vitreous seeding or optic nerve involvement, may be amenable to laser photocoagulation or transpupillary thermotherapy. Advanced tumors require enucleation, often with adjuvant chemotherapy and/or external beam radiotherapy. Risks of radiotherapy include retinal necrosis and radiation-induced tumors. Metastatic disease is treated with high-dose chemotherapy.
The overall mortality from retinoblastoma is 10 percent. After enucleation, optic nerve involvement beyond the point of surgical transection entails 65 percent mortality. Other adverse prognostic features include choroidal invasion, large tumor dimensions and poor cellular differentiation. Metastasis is rare. Other non-ocular primary tumors (e.g., osteogenic sarcoma or pinealoblastoma) will occur in 10 percent of patients.
Genetic counseling is necessary, and genetic tests are often conducted. For unaffected parents with one affected child, there is a 5 percent risk that a subsequent child will be affected. Patients with sporadic, unilateral retinoblastoma transmit the disease to approximately 10 percent of subsequent children. Those with germline mutations have a 50 percent chance of transmitting the mutation to each child.
Bisected globe with multiple white tumor deposits