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==Overview==
{{Retinoblastoma}}
{{Retinoblastoma}}
==Overview==
Retinoblastoma is the abnormal overgrowth of the [[retina]], the most inner layer of the eye. [[RB1]] [[gene]] [[mutation]] is the common [[cause]] of this [[malignancy]]. This [[tumor]] affects mostly young children and may result in loss of the [[vision]]. 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]]. 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 [[TNM|cTNMH systems]]. For extraocular [[diseases]], the International Retinoblastoma [[Cancer staging|Staging]] System (IRSS) and [[TNM Staging System|cTNMH]] schemes can be used. 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. Retinoblastoma may be caused by [[mutation]] in both [[allels]] of [[RB1]] [[tumor suppressor gene]] or due to somatic amplification of the ''MYCN'' [[oncogene]]. 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]]. 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]] associated with the development of retinoblastoma are [[mutation]] in [[RB1 gene]], a positive [[family history]] of retinoblastoma, living in areas with high [[incidence rate]] of the [[disease]], [[HPV]] viral exposure and other environmental factors. 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]]
'''Retinoblastoma''' is a [[cancer]] of the [[retina]]. Development of this tumor is initiated by [[mutation]]s<ref>{{cite journal |author=Knudson A |title=Mutation and cancer: statistical study of retinoblastoma |journal=Proc Natl Acad Sci U S A |volume=68 |issue=4 |pages=820-3 |year=1971 |pmid=5279gadgqetqer523}}</ref> that inactivate both copies of the ''[[RB1]]'' gene, which codes for the [[retinoblastoma protein]].<ref>{{cite journal |author=Friend S, Bernards R, Rogelj S, Weinberg R, Rapaport J, Albert D, Dryja T |title=A human DNA segment with properties of the gene that predisposes to retinoblastoma and osteosarcoma |journal=Nature |volume=323 |issue=6089 |pages=643-6 |year= |pmid=2877398}}</ref>It is a primitive neuroepithelial neoplasm. Retinal photoreceptor cells are developed from immature neural epithelium from which retinoblastoma is thought to arise from.<ref name="pmid7991814">{{cite journal |author=Smirniotopoulos JG, Bargallo N, Mafee MF |title=Differential diagnosis of leukokoria: radiologic-pathologic correlation |journal=[[Radiographics : a Review Publication of the Radiological Society of North America, Inc]] |volume=14 |issue=5 |pages=1059–79; quiz 1081–2 |year=1994 |month=September |pmid=7991814 |doi= |url=http://radiographics.rsnajnls.org/cgi/pmidlookup?view=long&pmid=7991814 |accessdate=2012-05-02}}</ref> It is also known as Retinal Neuroblastoma, Retinal Glioma and Retinal Glioblastoma. It occurs mostly in children younger than 5 years and accounts for about 3% of the cancers occurring in children younger than 15 years. Adult cases have also been clinically recorded.<ref>{{cite journal |author=Takahashi T, Tamura S, Inoue M, Isayama Y, Sashikata T |title=Retinoblastoma in a 26-year-old adult |journal=Ophthalmology |volume=90 |issue=2 |pages=179-83 |year=1983 |pmid=6856254}}</ref> The estimated annual incidence is approximately 4 per million children.<ref>[http://www.cancer.org/docroot/CRI/content CRI_2_4_1X_What_are_the_key_statistics_for_retinoblastoma_37.asp?sitearea= cancer.org]</ref> It begins with white blotches in one or both eyes ([[leukocoria]]) which can be seen in photographs (this is distinct from the [[red-eye effect]] which is normal); or when light reflects off the eye, as when watching television.The tumor may begin in one or both eyes. Retinoblastoma is usually confined to the eye but can spread to the brain via the [[optic nerve]].As the retina is the light-sensitive part of the eye necessary for vision, loss of vision occurs.
[[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. 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. [[Ultrasound imaging]] is the [[Gold standard (test)|gold standard test]] for the [[diagnosis]] of retinoblastoma. [[Magnetic resonance imaging|MRI]] can also be helpful in the [[diagnosis]] making. A common method of retinoblastoma [[classification]] is critical to plan treatment, evaluate [[prognosis]] and compare outcomes. Available grouping systems include the International Intraocular [[Retinoblastoma]] [[Classification]] (IIRC), Intraocular [[Classification]] of Retinoblastoma (ICRB) and [[TNM|cTNMH systems]] [[diseases]]. 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]]. 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. There are no [[diagnostic]] [[laboratory]] findings associated with retinoblastoma. There are no [[x-ray]] findings associated with retinoblastoma. On [[ultrasound imaging]], retinoblastoma is characterized by [[echogenic]] [[soft-tissue]] [[Mass|masses]] with variable shadowing due to [[Calcification|calcifications]] and heterogeneity due to [[necrosis]] and/or [[hemorrhage]]. [[CT scan]] has been the standard [[Imaging studies|imaging study]] of retinoblastoma. Retinoblastoma usually appears as an intra-[[ocular]] [[mass]] with [[calcification]] (in 80% of the cases). On [[head]] and [[neck]] [[MRI]], retinoblastoma is characterized by hyperintense [[mass]] on T1-weighted [[MRI]] and hypointense [[mass]] on T2-weighted [[MRI]]. [[Optical coherence tomography]] may be helpful in the [[diagnosis]] of Retinoblastoma. Other [[Diagnosis|diagnostic]] studies for retinoblastoma include [[fluorescein angiography]] and [[electroretinogram]]. The optimal [[therapy]] for retinoblastoma depends on the stage at [[diagnosis]]. [[Systemic]] [[chemotherapy]] via [[carboplatin]], [[etoposide]], and [[vincristine]] (CEV) is the most common regimen used to treat retinoblastoma. There are different modalities of treatment available for retinoblastoma. The feasibility of each strategy depends on the [[Cancer staging|stage]] of retinoblastoma at the time of [[diagnosis]]. There are no established measures for the [[Prevention (medical)|primary prevention]] of retinoblastoma. There are no established measures for the [[Prevention (medical)|secondary prevention]] of retinoblastoma.  
 
==Historic Perspective==
==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]].
In 1809 James Wardrop first described retinoblastoma was as a specific entity , with enucleation as his suggested treatment. Histologic studies including those of Flexner and Verhoeff and subsequent electron microscopy have given insights into its pathogenesis.<ref name="pmid3306547">{{cite journal| author=Albert DM| title=Historic review of retinoblastoma. | journal=Ophthalmology | year= 1987 | volume= 94 | issue= 6 | pages= 654-62 | pmid=3306547 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3306547  }} </ref>
 
==Classification==
==Classification==
Retinoblastoma may be classified into several subtypes based on the Reese-Ellsworth classification(REC), Essen classification, International retinoblastoma classification, International Retinoblastoma Staging System (IRSS) and the International Intraocular Retinoblastoma Classification (IIRC) or the ABC 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 [[TNM|cTNMH systems]]. For extraocular [[diseases]], the International Retinoblastoma [[Cancer staging|Staging]] System (IRSS) and [[TNM Staging System|cTNMH]] schemes can be used.
 
==Pathophysiology==
==Pathophysiology==
Development of this tumor is initiated by [[mutation]]s<ref>{{cite journal |author=Knudson A |title=Mutation and cancer: statistical study of retinoblastoma |journal=Proc Natl Acad Sci U S A |volume=68 |issue=4 |pages=820-3 |year=1971 |pmid=5279gadgqetqer523}}</ref> that inactivate both copies of the ''[[RB1]]'' gene, which codes for the [[retinoblastoma protein]].<ref>{{cite journal |author=Friend S, Bernards R, Rogelj S, Weinberg R, Rapaport J, Albert D, Dryja T |title=A human DNA segment with properties of the gene that predisposes to retinoblastoma and osteosarcoma |journal=Nature |volume=323 |issue=6089 |pages=643-6 |year= |pmid=2877398}}</ref>. The Retinoblastoma gene acts as a [[tumor suppressor]] gene.
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==
==Causes==
Retinoblastoma is caused by [[mutation]]s<ref>{{cite journal |author=Knudson A |title=Mutation and cancer: statistical study of retinoblastoma |journal=Proc Natl Acad Sci U S A |volume=68 |issue=4 |pages=820-3 |year=1971 |pmid=5279gadgqetqer523}}</ref> that inactivate both copies of the ''[[RB1]]'' gene, which codes for the [[retinoblastoma protein]].<ref>{{cite journal |author=Friend S, Bernards R, Rogelj S, Weinberg R, Rapaport J, Albert D, Dryja T |title=A human DNA segment with properties of the gene that predisposes to retinoblastoma and osteosarcoma |journal=Nature |volume=323 |issue=6089 |pages=643-6 |year= |pmid=2877398}}</ref>
Retinoblastoma may be caused by [[mutation]] in both [[allels]] of [[RB1]] [[tumor suppressor gene]] or due to somatic amplification of the ''MYCN'' [[oncogene]].
 
==Differentiating Retinoblastoma from Other Diseases==
==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]].
Retinoblastoma must be differentiated from other diseases that cause leucokoria, strabismus, vision problems and eye pain such as cataracts, retinopathy of prematurity and few more diseases.
==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.  
==Epidemiology and demographics==
The incidence of retinoblastoma worldwide ranges from 1 in 14,000 live births to 1 in 34,000.<ref name="pmid1145423">{{cite journal |author=Bishop JO, Madson EC |title=Retinoblastoma. Review of the current status |journal=[[Survey of Ophthalmology]] |volume=19 |issue=6 |pages=342–66 |year=1975 |pmid=1145423 |doi= |url= |accessdate=2012-05-02}}</ref>  The mean age-adjusted incidence rate of retinoblastoma is 11.8 cases per million children aged 0-4 years in the USA and it is similar to rates reported from European countries and the age-adjusted incidence rate of retinoblastoma in the USA as well as bilateral cases (26.7%) versus unilateral cases (71.9%) remained stable from 1975-2004.<ref name="pmid18621794">{{cite journal |author=Broaddus E, Topham A, Singh AD |title=Incidence of retinoblastoma in the USA: 1975-2004 |journal=[[The British Journal of Ophthalmology]] |volume=93 |issue=1 |pages=21–3 |year=2009 |month=January |pmid=18621794 |doi=10.1136/bjo.2008.138750 |url=http://bjo.bmj.com/cgi/pmidlookup?view=long&pmid=18621794 |accessdate=2012-05-02}}</ref> In a study which was done on 206 children with retinoblastoma, the mean age at diagnosis was 21.2 mo in the total study group and the mean age at diagnosis in the bilateral cases (14.6 months) was substantially less than in the unilateral ones (23.5 months) and the great majority of patients (approximately 75%) had advanced disease (group V in both Reese-Ellsworth and Essen prognosis classifications) in the affected eye (unilateral cases) or the more severely affected eye (bilateral cases).<ref name="pmid8537020">{{cite journal |author=Augsburger JJ, Oehlschläger U, Manzitti JE |title=Multinational clinical and pathologic registry of retinoblastoma. Retinoblastoma International Collaborative Study report 2 |journal=[[Graefe's Archive for Clinical and Experimental Ophthalmology = Albrecht Von Graefes Archiv Für Klinische Und Experimentelle Ophthalmologie]] |volume=233 |issue=8 |pages=469–75 |year=1995 |month=August |pmid=8537020 |doi= |url= |accessdate=2012-05-02}}</ref>. There is no predilection for retinoblastoma by race or gender. Right and left eyes are affected equally. It is the most common intraocular tumor of the childhood.
 
==Risk factors==
==Risk factors==
Development of this tumor is initiated by [[mutation]]s<ref>{{cite journal |author=Knudson A |title=Mutation and cancer: statistical study of retinoblastoma |journal=Proc Natl Acad Sci U S A |volume=68 |issue=4 |pages=820-3 |year=1971 |pmid=5279gadgqetqer523}}</ref> that inactivate both copies of the ''[[RB1]]'' gene, which codes for the [[retinoblastoma protein]].<ref>{{cite journal |author=Friend S, Bernards R, Rogelj S, Weinberg R, Rapaport J, Albert D, Dryja T |title=A human DNA segment with properties of the gene that predisposes to retinoblastoma and osteosarcoma |journal=Nature |volume=323 |issue=6089 |pages=643-6 |year= |pmid=2877398}}</ref> While the genetics of retinoblastoma are well understood, there is much less known about the non-genetic factors in retinoblastoma.
[[Risk factors]] associated with the development of retinoblastoma are [[mutation]] in [[RB1 gene]], a positive [[family history]] of retinoblastoma, living in areas with high [[incidence rate]] of the [[disease]], [[HPV]] viral exposure and other [[Environmental factor|environmental factors]].
 
==Screening==
==Screening==
According to American Academy of Pediatrics policy statement on Red Reflex Examinations in Neonates, Infants, and Children <ref>http://eyewiki.org/Retinoblastoma#cite_ref-AAP_4-0</ref> for retinoblastoma recommends that all neonates, infants, and children should have an examination of the red reflex before discharge from the neonatal nursery and at all subsequent routine health supervision visits.
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==
==Natural history, Complications, and Prognosis==
Retinoblastoma is a rapidly growing tumor. If left untreated, the tumor fills the eye and completely destroys the globe in six months. Metastatic spread begins after six months and metastasized tumor is very rare at presentation. The tumor may spread through the subarachnoid space to the contralateral optic nerve or through the cerebrospinal fluid to the central nervous system or hematogenously to the lung, bone, or brain or by lymphatics if the tumor spreads anteriorly into the conjunctivae and eyelids, or extends into extraocular tissue.  The most common routes of metastatic spread are direct infiltration via the optic nerve to the central nervous system, or spread via the choroid to the orbit.
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 [[Patient|patients]] die of [[Cranium|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.
If untreated, death usually occurs in few years.
==Daignosis==
 
===Diagnostic Study of Choice===
==History and symptoms==
[[Ultrasound imaging]] is the [[Gold standard (test)|gold standard test]] for the [[diagnosis]] of retinoblastoma. [[Magnetic resonance imaging|MRI]] can also be helpful in the [[diagnosis]] making. A common method of retinoblastoma [[classification]] is critical to plan treatment, evaluate [[prognosis]] and compare outcomes. Available grouping systems include the International Intraocular [[Retinoblastoma]] [[Classification]] (IIRC), Intraocular [[Classification]] of Retinoblastoma (ICRB) and [[TNM|cTNMH systems]] [[diseases]].
Approximately 6% of the retinoblastoma is familial.<ref name="pmid15377991">{{cite journal |author=Shields CL, Shields JA |title=Diagnosis and management of retinoblastoma |journal=[[Cancer Control : Journal of the Moffitt Cancer Center]] |volume=11 |issue=5 |pages=317–27 |year=2004 |pmid=15377991 |doi= |url=http://www.moffitt.org/CCJRoot/v11n5/pdf/317.pdf |accessdate=2012-05-29}}</ref> So family history should be inquired whenever there is suspicion of retinoblastoma.
 
==Physical examination==
Common physical examination findings of retinoblastoma include leukocoria, retinal detachment, vitreal opacification and hemorrhage, the diagnosis is challenging.
 
==CT scan==
CT scan may be helpful in the diagnosis of retinoblastoma.
 
==MRI scan==
'''High-resolution contrast enhanced MRI''' is the diagnostic technique of choice and the '''most sensitive technique''' for evaluating retinoblastoma.
 
==Ultrasound==
On ultrasound, retinoblastoma is characterized by an irregular mass, more [[echogenic]] than the [[vitreous]] body, with fine [[calcifications]] (highly reflective foci mostly with characteristic acoustic shadowing).The vitreous may have echogenic debris from hemorrhage, increased globulin content, or tumor seeding.
 
==Other imaging studies==
Bone scan may be helpful in the diagnosis of retinoblastoma metastasis.
 
==Other diagnostic finding==
Bone marrow examination or lumbar puncture may also be performed in patients where there is concern regarding the extent of disease; particularly with extraocular extension to rule out cerebrospinal fluid (CSF) or bone marrow metastases.
 
==Medical therapy==
Treatment modalities for retinoblastoma that may be successful in globe salvage include systemic chemotherapy with focal consolidation, intra-arterial chemotherapy, and for small tumors, focally destructive therapy (cryopexy, laser photocoagulation, hyperthermia and plaque irradiation).<ref>http://eyewiki.org/Retinoblastoma#General_treatment</ref> Minimizing side effects and complications of treatment are also of paramount importance in these very young patients.
 
==Surgical therapy==
Enucleation remains the definitive treatment of intraocular retinoblastoma, particularly in the majority of patients who present with unilateral disease.


===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===
[[Patient|Patients]] with retinoblastoma usually appear normal. [[Physical examination]] of [[Patient|patients]] is usually remarkable for [[leukocoria]], [[strabismus]], and [[proptosis]], particularly in advanced cases. Other findings on [[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 [[Fundoscopy|fundoscopic examination]].


===Laboratory Findings===
There are no [[diagnostic]] [[laboratory]] findings associated with retinoblastoma.
===Electrocardiogram===
There are no [[ECG]] findings associated with retinoblastoma.
===X Ray===
There are no [[x-ray]] findings associated with retinoblastoma.
===Echocardiography and Ultrasound===
On [[ultrasound imaging]], retinoblastoma is characterized by echogenic [[Soft tissue|soft-tissue]] [[Mass|masses]] with variable shadowing due to [[calcification]] and [[heterogeneity]] due to [[necrosis]] and/or [[hemorrhage]].
===CT scan===
[[CT scan]] has been the standard [[Imaging studies|imaging study]] of retinoblastoma. Retinoblastoma usually appears as an intra-[[ocular]] [[mass]] with [[calcification]] (in 80% of the cases).
===MRI scan===
[[Magnetic resonance imaging|MRI]] findings of retinoblastoma include hyperintense [[mass]] on T1-weighted [[MRI]] and hypointense [[mass]] on T2-weighted [[MRI]].
===Other Imaging Findings===
[[Optical coherence tomography]] may be helpful in the [[diagnosis]] of Retinoblastoma.
===Other Diagnostic Studies===
Other [[Diagnosis|diagnostic]] studies for retinoblastoma include [[fluorescein angiography]] and [[electroretinogram]].
==Treatment==
===Medical therapy===
The optimal [[therapy]] for retinoblastoma depends on the stage at [[diagnosis]]. [[Systemic]] [[chemotherapy]] via [[carboplatin]], [[etoposide]], and [[vincristine]] (CEV) is the most common regimen used to treat retinoblastoma.
===Surgery===
There are different modalities of treatment available for retinoblastoma. The feasibility of each strategy depends on the [[Cancer staging|stage]] of retinoblastoma at the time of [[diagnosis]].
===Primary Prevention===
There are no established measures for the [[Prevention (medical)|primary prevention]] of retinoblastoma.
===Secondary Prevention===
There are no established measures for the [[Prevention (medical)|secondary prevention]] of retinoblastoma. 
==References==
==References==
{{reflist|2}}
{{reflist|2}}
<references/>
==See also==
*[[Eye cancer]]
*[[Eye examination]]
{{Nervous tissue tumors}}
[[Category:Ophthalmology]]
[[Category:Types of cancer]]
[[Category:hereditary cancers]]
[[Category:Oncology stub]]


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Latest revision as of 23:59, 29 July 2020

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sahar Memar Montazerin, M.D.[2] Simrat Sarai, M.D. [3]

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Retinoblastoma is the abnormal overgrowth of the retina, the most inner layer of the eye. RB1 gene mutation is the common cause of this malignancy. This tumor affects mostly young children and may result in loss of the vision. 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. 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. 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. Retinoblastoma may be caused by mutation in both allels of RB1 tumor suppressor gene or due to somatic amplification of the MYCN oncogene. 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. 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 associated with the development of retinoblastoma are mutation in RB1 gene, a positive family history of retinoblastoma, living in areas with high incidence rate of the disease, HPV viral exposure and other environmental factors. 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. 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. Ultrasound imaging is the gold standard test for the diagnosis of retinoblastoma. MRI can also be helpful in the diagnosis making. A common method of retinoblastoma classification is critical to plan treatment, evaluate prognosis and compare outcomes. Available grouping systems include the International Intraocular Retinoblastoma Classification (IIRC), Intraocular Classification of Retinoblastoma (ICRB) and cTNMH systems diseases. 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. 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. There are no diagnostic laboratory findings associated with retinoblastoma. There are no x-ray findings associated with retinoblastoma. On ultrasound imaging, retinoblastoma is characterized by echogenic soft-tissue masses with variable shadowing due to calcifications and heterogeneity due to necrosis and/or hemorrhage. 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). On head and neck MRI, retinoblastoma is characterized by hyperintense mass on T1-weighted MRI and hypointense mass on T2-weighted MRI. Optical coherence tomography may be helpful in the diagnosis of Retinoblastoma. Other diagnostic studies for retinoblastoma include fluorescein angiography and electroretinogram. The optimal therapy for retinoblastoma depends on the stage at diagnosis. Systemic chemotherapy via carboplatin, etoposide, and vincristine (CEV) is the most common regimen used to treat retinoblastoma. There are different modalities of treatment available for retinoblastoma. The feasibility of each strategy depends on the stage of retinoblastoma at the time of diagnosis. There are no established measures for the primary prevention of retinoblastoma. There are no established measures for the secondary prevention of retinoblastoma.

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 may be caused by mutation in both allels of RB1 tumor suppressor gene or due to somatic amplification of the MYCN oncogene.

Differentiating Retinoblastoma from Other Diseases

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

Risk factors associated with the development of retinoblastoma are mutation in RB1 gene, a positive family history of retinoblastoma, living in areas with high incidence rate of the disease, HPV viral exposure and other environmental factors.

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.

Daignosis

Diagnostic Study of Choice

Ultrasound imaging is the gold standard test for the diagnosis of retinoblastoma. MRI can also be helpful in the diagnosis making. A common method of retinoblastoma classification is critical to plan treatment, evaluate prognosis and compare outcomes. Available grouping systems include the International Intraocular Retinoblastoma Classification (IIRC), Intraocular Classification of Retinoblastoma (ICRB) and cTNMH systems diseases.

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 on 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 Findings

There are no diagnostic laboratory findings associated with retinoblastoma.

Electrocardiogram

There are no ECG findings associated with retinoblastoma.

X Ray

There are no x-ray findings associated with retinoblastoma.

Echocardiography and Ultrasound

On ultrasound imaging, retinoblastoma is characterized by echogenic soft-tissue masses with variable shadowing due to calcification and heterogeneity due to necrosis and/or hemorrhage.

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

MRI findings of retinoblastoma include hyperintense mass on T1-weighted MRI and hypointense mass on T2-weighted MRI.

Other Imaging Findings

Optical coherence tomography may be helpful in the diagnosis of Retinoblastoma.

Other Diagnostic Studies

Other diagnostic studies for retinoblastoma include fluorescein angiography and electroretinogram.

Treatment

Medical therapy

The optimal therapy for retinoblastoma depends on the stage at diagnosis. Systemic chemotherapy via carboplatin, etoposide, and vincristine (CEV) is the most common regimen used to treat retinoblastoma.

Surgery

There are different modalities of treatment available for retinoblastoma. The feasibility of each strategy depends on the stage of retinoblastoma at the time of diagnosis.

Primary Prevention

There are no established measures for the primary prevention of retinoblastoma.

Secondary Prevention

There are no established measures for the secondary prevention of retinoblastoma.

References