Download Solid Tumour Section Head and Neck: Retinoma Atlas of Genetics and Cytogenetics

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in Oncology and Haematology
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Solid Tumour Section
Short Communication
Head and Neck: Retinoma
Helen Dimaras
Division of Hematology and Oncology, The Hospital for Sick Children, Toronto, ON, Canada (HD)
Published in Atlas Database: March 2012
Online updated version : http://AtlasGeneticsOncology.org/Tumors/RetinomaID5049.html
DOI: 10.4267/2042/47543
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 France Licence.
© 2012 Atlas of Genetics and Cytogenetics in Oncology and Haematology
Identity
Clinics and pathology
Other names
Retinocytoma
Note
Retinoma is the benign precursor to the childhood eye
tumor, retinoblastoma. In rare cases, it remains benign
for the lifetime of the individual, never progressing to
retinoblastoma. Retinoma has three (3) characteristic
clinical features: a grey, translucent mass in the retina;
cottage cheese-like calcification; and a hyperplastic
retinal epithelium/chorioretinal scar (Gallie et al.,
1982). Vitreous seeds have also been observed
associated with retinoma (Lueder et al., 1995).
Note
The diagnosis of retinoma is made by clinical
observation. Evidence of retinoma in eyes removed for
retinoblastoma is often observed by histology (Dimaras
et al., 2008; Eagle, 2009), and sometimes clinically
after treatment of the overlying retinoblastoma tumor
(Dimaras et al., 2009).
Epidemiology
Retinoma has been observed clinically in 1.8% (Gallie
et al., 1982) to 3.2% (Abouzeid et al., 2012) of
retinoblastoma cases and by pathology in 15.6%
(Dimaras et al., 2008) to 20.4% (Eagle, 2009) of
enucleated retinoblastoma specimens.
Retinoma showing classic features of chorioretinal scar, translucent retinal mass and calcification.
Atlas Genet Cytogenet Oncol Haematol. 2012; 16(9)
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Head and Neck: Retinoma
Dimaras H
Retinoma histology showing abundant fleurettes and sparse cells with eosinophilic cytoplasm.
Pathology
Prognosis
Retinoma is histologically distinct from its malignant
counterpart, retinoblastoma.
Retinoma displays abundant fleurettes, eosinophilic
cytoplasm, foci of calcification and non-proliferative
cells (Margo et al., 1983; Dimaras et al., 2008).
Retinoma lacks the typical features of retinoblastoma
(Homer Wright and Flexner-Wintersteiner rosettes,
nuclear molding, abundant mitoses and necroses), and
is often observed adjacent to retinoblastoma tumor in
enucleated specimens (Dimaras et al., 2008).
Retinoma is by definition benign and does not pose any
threat to life, thought it may interfere with vision.
Regular examination of rare individuals with retinoma
is necessary to spot any sign of malignant
transformation to retinoblastoma.
Cytogenetics
Note
Retinomas identified histologically adjacent to
retinoblastomas have been studied by FISH. Retinomas
display low level genomic copy number changes in
several genes altered to a higher degree in adjacent
retinoblastoma tumors (Gain: KIF14, DEK, E2F3,
MYCN; Loss: CDH11), suggesting a shared origin
(Dimaras et al., 2008).
The altered copy number changes in retinoma are not
manifested at the expression level as in retinoblastoma.
Treatment
Frequent ophthalmic examination monitors for
potential malignant progression. Malignant progression
is more common in children with retinoma than in
adults. In a child, the physician may opt to treat
retinoma as retinoblastoma if there is even a minor
suspicion of malignant progression.
Evolution
Genes involved and proteins
Because retinomas share the same genetic origin as
retinoblastoma and are frequently observed adjacent to
retinoblastoma in pathological specimens, it is
hypothesized that every retinoblastoma passes through
a retinoma stage. However, rare retinomas do not ever
progress to retinoblastoma. The difference between the
retinomas that progress to malignancy and those that do
not is unknown. Benign cystic growth has also been
observed in some retinomas (Sampieri et al., 2008;
Abouzeid et al., 2012).
Atlas Genet Cytogenet Oncol Haematol. 2012; 16(9)
Note
Like retinoblastoma, retinoma is initiated by the loss of
both copies of the RB1 tumor suppressor gene.
RB1 (Retinoblastoma tumor supressor
gene)
Location
13q14.2
681
Head and Neck: Retinoma
Dimaras H
Note
Retinoma is initiated by the loss of both copies of the
RB1 gene.
Adjacent specimens of retinoblastoma and retinoma
display the same mutation(s) in RB1 (Dimaras et al.,
2008).
DNA / RNA
DNA: 27 exons, 180 kb genomic DNA; RNA: 4840 bp
mRNA transcript.
Protein
928 amino acid phosphoprotein.
References
Gallie BL, Ellsworth RM, Abramson DH, Phillips RA. Retinoma:
spontaneous regression of retinoblastoma or benign
manifestation of the mutation? Br J Cancer. 1982
Apr;45(4):513-21
Margo C, Hidayat A, Kopelman J, Zimmerman LE.
Retinocytoma. A benign variant of retinoblastoma. Arch
Ophthalmol. 1983 Oct;101(10):1519-31
Lueder GT, Héon E, Gallie BL. Retinoma associated with
vitreous seeding. Am J Ophthalmol. 1995 Apr;119(4):522-3
Dimaras H, Khetan V, Halliday W, Orlic M, Prigoda NL,
Piovesan B, Marrano P, Corson TW, Eagle RC Jr, Squire JA,
Gallie BL. Loss of RB1 induces non-proliferative retinoma:
increasing genomic instability correlates with progression to
retinoblastoma. Hum Mol Genet. 2008 May 15;17(10):1363-72
CDKN2A (p16INK4A)
Location
9p21.3
Note
Retinoma is marked by upregulation of p16INK4A
mRNA and protein, which is not observed in
retinoblastoma.
The upregulation of the senescence-associated protein
may account for the non-proliferative nature of
retinoma (Dimaras et al., 2008).
DNA / RNA
DNA: 3 exons, 6.6 kb genomic DNA; RNA: 471 bp
mRNA transcript.
Protein
156 amino acid protein.
Sampieri K, Mencarelli MA, Epistolato MC, Toti P, Lazzi S,
Bruttini M, De Francesco S, Longo I, Meloni I, Mari F,
Acquaviva A, Hadjistilianou T, Renieri A, Ariani F. Genomic
differences between retinoma and retinoblastoma. Acta Oncol.
2008;47(8):1483-92
Dimaras H, Khetan V, Halliday W, Héon E, Chan HS, Gallie
BL. Retinoma underlying retinoblastoma revealed after tumor
response to 1 cycle of chemotherapy. Arch Ophthalmol. 2009
Aug;127(8):1066-8
Eagle RC Jr. High-risk features and tumor differentiation in
retinoblastoma: a retrospective histopathologic study. Arch
Pathol Lab Med. 2009 Aug;133(8):1203-9
Abouzeid H, Balmer A, Moulin AP, Mataftsi A, Zografos L,
Munier FL. Phenotypic variability of retinocytomas:
preregression and postregression growth patterns. Br J
Ophthalmol. 2012 Jun;96(6):884-9
This article should be referenced as such:
Dimaras H. Head and Neck: Retinoma. Atlas Genet Cytogenet
Oncol Haematol. 2012; 16(9):680-682.
Atlas Genet Cytogenet Oncol Haematol. 2012; 16(9)
682