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MRI Features for Identifying MYCN -amplified RB1 Wild-type Retinoblastoma
Journal article   Peer reviewed

MRI Features for Identifying MYCN -amplified RB1 Wild-type Retinoblastoma

Robin W Jansen, Christiaan M de Bloeme, Liesbeth Cardoen, Sophia Göricke, Sabien van Elst, Jaime Lyn Jessen, Aparna Ramasubramanian, Alison H Skalet, Audra K Miller, Philippe Maeder, …
Radiology, Vol.307(5), e222264
06/2023
DOI: 10.1148/radiol.222264
PMCID: PMC10315525
PMID: 37191489
url
https://pmc.ncbi.nlm.nih.gov/articles/PMC10315525/pdf/radiol.222264.pdfView
Open Access

Abstract

MYCN-amplified RB1 wild-type retinoblastoma has distinct features compared with RB1 pathogenic variant–driven retinoblastoma at MRI, including tumors in a peripheral (anterior) location with plaque or pleomorphic shape, irregular margins, tumor-retinal folding, and peritumoral blood. Background MYCN-amplified RB1 wild-type (MYCNARB1+/+) retinoblastoma is a rare but clinically important subtype of retinoblastoma due to its aggressive character and relative resistance to typical therapeutic approaches. Because biopsy is not indicated in retinoblastoma, specific MRI features might be valuable to identify children with this genetic subtype. Purpose To define the MRI phenotype of MYCNARB1+/+ retinoblastoma and evaluate the ability of qualitative MRI features to help identify this specific genetic subtype. Materials and Methods In this retrospective, multicenter, case-control study, MRI scans in children with MYCNARB1+/+ retinoblastoma and age-matched children with RB1−/− subtype retinoblastoma were included (case-control ratio, 1:4; scans acquired from June 2001 to February 2021; scans collected from May 2018 to October 2021). Patients with histopathologically confirmed unilateral retinoblastoma, genetic testing (RB1/MYCN status), and MRI scans were included. Associations between radiologist-scored imaging features and diagnosis were assessed with the Fisher exact test or Fisher-Freeman-Halton test, and Bonferroni-corrected P values were calculated. Results A total of 110 patients from 10 retinoblastoma referral centers were included: 22 children with MYCNARB1+/+ retinoblastoma and 88 control children with RB1−/− retinoblastoma. Children in the MYCNARB1+/+ group had a median age of 7.0 months (IQR, 5.0–9.0 months) (13 boys), while children in the RB1−/− group had a median age of 9.0 months (IQR, 4.6–13.4 months) (46 boys). MYCNARB1+/+ retinoblastomas were typically peripherally located (in 10 of 17 children; specificity, 97%; P < .001) and exhibited plaque or pleomorphic shape (in 20 of 22 children; specificity, 51%; P = .011) with irregular margins (in 16 of 22 children; specificity, 70%; P = .008) and extensive retina folding with vitreous enclosure (specificity, 94%; P < .001). MYCNARB1+/+ retinoblastomas showed peritumoral hemorrhage (in 17 of 21 children; specificity, 88%; P < .001), subretinal hemorrhage with a fluid-fluid level (in eight of 22 children; specificity, 95%; P = .005), and strong anterior chamber enhancement (in 13 of 21 children; specificity, 80%; P = .008). Conclusion MYCNARB1+/+ retinoblastomas show distinct MRI features that could enable early identification of these tumors. This may improve patient selection for tailored treatment in the future.

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