Retinoblastoma overview: Difference between revisions
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Other imaging studies for retinoblastoma include wide-field [[fundus]] photography and spectral domain optical coherence tomography. | Other imaging studies for retinoblastoma include wide-field [[fundus]] photography and spectral domain optical coherence tomography. | ||
==Other Diagnostic Studies== | ==Other Diagnostic Studies== | ||
Other diagnostic studies for retinoblastoma include [[fluorescein angiography | Other diagnostic studies for retinoblastoma include [[fluorescein angiography]]. | ||
==Medical therapy== | ==Medical therapy== | ||
The optimal therapy for retinoblastoma depends on several factors such as [[tumor]] size, tumor location, presence or absence of [[vitreous]] or subretinal seeds, and patient age. The various treatment modalities for retinoblastoma include [[enucleation]], external beam [[radiation therapy]], radioactive plaques (I-125 [[brachytherapy]]), [[cryotherapy]], [[laser photocoagulation]], [[thermotherapy]], and [[chemotherapy]] (which includes systemic, intra-arterial, and [[intravitreal]]). | The optimal therapy for retinoblastoma depends on several factors such as [[tumor]] size, tumor location, presence or absence of [[vitreous]] or subretinal seeds, and patient age. The various treatment modalities for retinoblastoma include [[enucleation]], external beam [[radiation therapy]], radioactive plaques (I-125 [[brachytherapy]]), [[cryotherapy]], [[laser photocoagulation]], [[thermotherapy]], and [[chemotherapy]] (which includes systemic, intra-arterial, and [[intravitreal]]). | ||
Revision as of 19:02, 17 May 2019
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1],Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
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Retinoblastoma Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Retinoblastoma overview On the Web |
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American Roentgen Ray Society Images of Retinoblastoma overview |
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Risk calculators and risk factors for Retinoblastoma overview |
Overview
Retinoblastoma is the most common malignant intraocular tumor in children. Retinoblastoma may be classified into several subgroups based on the International Retinoblastoma Staging System (IRSS). On gross pathology, viable tumor cells near blood vessels and zones of necrosis in avascular areas are characteristic findings of retinoblastoma. On microscopic histopathological analysis, a small round-cell tumor of neuroepithelial origin, Flexner-Wintersteiner rosettes, and Homer-Wright rosettes are characteristic findings of retinoblastoma. Retinoblastoma can be bilateral or unilateral, spontaneous or familial. In 30% to 40% of cases, retinoblastoma is accompanied by a germinal mutation in the RB1 gene. The incidence of retinoblastoma in the United States is approximately 0.43 cases per 100,000 children under 15 years of age. The median age at diagnosis of retinoblastoma is 18 months. The average age at diagnosis of retinoblastoma for children with bilateral and unilateral disease is 12 months and 24 months respectively. Retinoblastoma affects males and females equally. There is no racial predilection to the development of retinoblastoma. Common risk factors in the development of retinoblastoma are advanced paternal age, positive family history, and viral exposure. The hallmark of retinoblastoma is leukocoria which is an abnormal appearance of the retina as viewed through the pupil, also known as amaurotic cat's eye reflex. A positive family history of retinoblastoma may be present. Less common symptoms of retinoblastoma include deterioration of vision, a red and irritated eye, eye pain, proptosis, and fever. Common physical examination findings of retinoblastoma include leukocoria, strabismus, proptosis, anisocoria, orbital cellulitis, hyphema, heterochromia iridis, poor vision, unilateral mydriasis, rubeosis iridis, vitreous hemorrhage, and findings of chalky white-gray retinal mass on fundoscopic examination. The optimal therapy for retinoblastoma depends on several factors such as tumor size, tumor location, presence or absence of vitreous or subretinal seeds, and patient age. The various treatment modalities for retinoblastoma include, enucleation, external beam radiation therapy, radioactive plaques (I-125 brachytherapy), cryotherapy, laser photocoagulation, thermotherapy, and chemotherapy (which includes systemic, intra-arterial, and intravitreal). When the retinoblastoma is too large to be treated by other treatment modalities, surgery may be used. In these situations, enucleation may help to prevent metastasis.
Historic Perspective
Retinoblastoma was first described in 1809 by Dr. James Wardrop. Then, Dr. Flexner, in 1891, was the first to discover the rosette structure within the tumor.In 1953, Dr. Kupfer was the first ophthalmologist who tried a combination of chemotherapy and radiotherapy for the treatment of the tumor.
Classification
There are several classification system available for retinoblastoma. As the treatment of the tumor has evolved, a new classification system has been introduced. For intraocular diseases the available grouping systems include the International Intraocular Retinoblastoma Classification (IIRC), Intraocular Classification of Retinoblastoma (ICRB) and cTNMH systems. For extraocular diseases, the International Retinoblastoma Staging System (IRSS) and cTNMH schemes can be used.
Pathophysiology
Retinoblastoma is a neoplasm which is caused by the inactivation of RB1 gene, a tumor suppressor gene, located on the long arm of the chromosome 13. Mutation in both alleles of the RB1 gene is necessary for the inactivation of the gene. This disorder may occur in the familial or sporadic form. (Rb) gene product limits the cell progression from the G1 phase to the S phase of the cell cycle. Loss of this active, functional protein (Rb) causes cell cycle dysregulation and subsequent overgrowth and tumor formation.
Causes
Retinoblastoma is caused by a mutation in the RB1 gene.
Differential Diagnosis
Retinoblastoma must be differentiated from other diseases that cause leukocoria. leukocoria may occur in several ocular conditions including tumors, vascular disease, inflammatory disorders, and also due to trauma.
Epidemiology and Demographics
The incidence of retinoblastoma in the United States has been reported 1.2 cases per 100,000 child aged 4 years or younger. The median age at diagnosis of retinoblastoma is 18 months. The average age at diagnosis of retinoblastoma for children with unilateral disease and bilateral disease is 24 months and 12 months respectively. Retinoblastoma affects males and females equally. There is no racial predilection to the development of retinoblastoma.
Risk factors
Common risk factors in the development of retinoblastoma are advanced paternal age, positive family history, and viral exposure.
Screening
Early diagnosis of retinoblastoma is necessary to obtain the best outcomes for vision and eye salvage. In 2018, a group of experts in clinical retinoblastoma care and ophthalmic pathology and genetics suggest a risk-stratified schedule for ophthalmic screening examinations. Estimated risk of retinoblastoma development is calculated according to the relativity of individuals to the family member with retinoblastoma.
Natural history,Complications and Prognosis
If left untreated, retinoblastoma may progress to develop seeding in the eye, leading to retinal detachment, necrosis and invasion of the orbit, optic nerve invasion, and central nervous system invasion. The majority of untreated patients die of intracranial extension and disseminated disease within one year. Spontaneous regression of the tumor is a rare occurrence but may occur in a small number of cases. Common complications of retinoblastoma include metastasis, tumor recurrence, trilateral retinoblastoma, and subsequent neoplasms. Prognosis is generally good, and the survival rate of patients with retinoblastoma with treatment is approximately 95% in the United States.
History and Symptoms
The hallmark of retinoblastoma is leukocoria which is an abnormal appearance of the retina as viewed through the pupil, also known as amaurotic cat's eye reflex. Other common symptoms include strabismus and proptosis. The clinical presentation depends on the stage of the disease.
Physical Examination
Patients with retinoblastoma usually appear normal. Physical examination of patients is usually remarkable for leukocoria, strabismus, and proptosis, particularly in advanced cases. Other findings in physical examination of retinoblastoma include anisocoria, orbital cellulitis, hyphema, heterochromia iridis, poor visual acuity, unilateral mydriasis, rubeosis iridis, vitreous hemorrhage, and findings of intrinsic calcification on fundoscopic examination.
Laboratory Tests
There are no diagnostic lab findings associated with retinoblastoma.
Chest X Ray
There are no chest x-ray findings associated with retinoblastoma.
CT scan
CT scan has been the standard imaging study of retinoblastoma. Retinoblastoma usually appears as an intra-ocular mass with calcification (in 80% of the cases).
MRI scan
On head and neck MRI, retinoblastoma is characterized by hyperintense mass on T1-weighted MRI and hypointense mass on T2-weighted MRI.
Ultrasound
On ultrasound, retinoblastoma is characterized by echogenic soft-tissue masses with variable shadowing due to calcifications and heterogeneity due to necrosis and/or hemorrhage.
Other Imaging Studies
Other imaging studies for retinoblastoma include wide-field fundus photography and spectral domain optical coherence tomography.
Other Diagnostic Studies
Other diagnostic studies for retinoblastoma include fluorescein angiography.
Medical therapy
The optimal therapy for retinoblastoma depends on several factors such as tumor size, tumor location, presence or absence of vitreous or subretinal seeds, and patient age. The various treatment modalities for retinoblastoma include enucleation, external beam radiation therapy, radioactive plaques (I-125 brachytherapy), cryotherapy, laser photocoagulation, thermotherapy, and chemotherapy (which includes systemic, intra-arterial, and intravitreal).
Surgical therapy
The feasibility of surgery depends on the tumor size, tumor location, and presence or absence of vitreous or subretinal seeds at diagnosis. When the retinoblastoma is too large to be treated by other treatment modalities, surgery may be used. In these situations, enucleation may help to prevent metastasis.
Primary Prevention
There are no primary preventive measures available for retinoblastoma.
Secondary Prevention
Early diagnosis of retinoblastoma is necessary to obtain the best outcomes for vision and eye salvage. In 2018, a group of experts in clinical retinoblastoma care and ophthalmic pathology and genetics suggest a risk-stratified schedule for ophthalmic screening examinations. Estimated risk of retinoblastoma development is calculated according to the relativity of individuals to the family member with retinoblastoma.
References