Retinoblastoma

A familial malignant ocular embryonic tumor develops in the retina because of a defect in a regulatory gene. Prognosis is good. Association with other primary malignancies is frequent.

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RB.

Estimated at 1:16,000 to 23,000 live births in the United States. Over 90% are diagnosed before the age of 5 years. Nonwhite individuals present with a prevalence four times greater than whites. Bilateral cases occur in 20%.

In general, 5 to 10% of cases are inherited, 20 to 30% are new germinal mutations, and 60 to 70% are sporadic (unilateral mainly). Most (90%) bilateral cases are familial. Retinoblastoma gene (Rb) gene is located at 13q14.1-q14.2.

Usually develop in posterior portion of retina with multiple foci. Typically invade locally and grow forward into vitreous or backward into optic nerve. Rarely metastasize until very late. Rb gene is thought to have a suppressor function. Retinoblastoma would occur by loss or inactivation of both alleles of this gene. There is a high incidence of second primary tumors, suggesting a key role in the etiology of several other primary malignancies (osteogenic sarcoma, pinealoma, leukemia, lymphoma, and Ewing sarcoma).

Clinical features and careful ophthalmologic examination. CT and MRI assessment of the eye and orbit is also recommended. Median age at diagnosis is 11 months for bilateral disease and 23 months for unilateral disease.

Early presenting feature is leukocoria (white “cat's eye” reflex), a yellowish-white reflex in the pupil caused by tumor behind the lens. Other common findings include diminishing or absent vision and strabismus. In more advanced disease, there may be pupillary irregularity, hyphema, and pain. Severe disease may have ptosis, raised intracranial pressure, and bone metastasis. Treatment includes cryotherapy, laser ablation, local radiation, and, finally, enucleation. Overall survival is greater than 90%. There is a high risk of other malignancies, particularly osteogenic sarcoma and other germ cell tumors. Retinoblastoma may occur in association with other “13q-syndromes,” which are typically characterized by growth delay, mental retardation, and minor facial anomalies.

These patients often come to the operating room for examination, laser therapy, cryotherapy, radiotherapy, or staging. A review of the chemotherapy and steroid administration must be obtained. Overall, medical condition must be reviewed.

There are no specific considerations in isolated form. With multiple and frequent general anesthesia, good rapport with patient and family is important. If laser ablation is used, considerations include laser safety and immobility during laser use. All anesthesia considerations associated to radiotherapy treatment must be applied.

Probably avoid anesthetic drugs ...