Distinctive MRI Features of Pediatric Medulloblastoma Subtypes

Yeom, Kristen W.; Mobley, Bret; Lober, Robert M.; Andre, Jalal B.; Partap, Sonia; Vogel, Hannes; Barnes, Patrick D.

doi:10.2214/ajr.12.9249

Cited by 102 publications

(80 citation statements)

References 35 publications

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“…Classical MB is typically hypointense on T1W and hyperintense on T2W with restricted diffusion and variable enhancement (4). Anaplastic MB is associated with increased apparent diffusion coefficient (ADC) value and ring enhancement (10).…”

Section: Discussionmentioning

confidence: 99%

Medulloblastoma with Suprasellar Extension and Atypical Presentation

et al. 2017

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A 6-year-old boy was referred with symptoms of right partial ptosis, blurred vision and a two-week history of poor coordination and frequent falls. No symptoms of raised intracranial pressure were demonstrated. Imaging showed a large sella mass with extension into the posterior fossa and suprasellar region, suggestive of a craniopharyngioma. Histopathological examination of the postsurgical resection specimen revealed a small blue cell tumor consistent with a medulloblastoma. This case aims to highlight a posterior fossa tumor with an unusual spread and thus clinical presentation.Keywords: Medulloblastoma, Pediatrics Case PresentationA 6-year-old boy was referred to our ophthalmology unit from a district hospital for further investigation on his symptoms of blurred vision and right partial ptosis of two weeks duration. He initially presented to the district hospital following a fall from a staircase. Further history from the child's father revealed that the child seemed uncoordinated. He had fallen several times in the previous two weeks. He dragged his left foot when walking suggesting a left lower limb weakness. He denied any headache or vomiting.On examination, there was a relative afferent pupillary defect over the right eye with partial ptosis and the eyeball turned outward and downward. There was pallor of the optic disc suggestive of compression of the optic nerve. The left fundus examination was normal.Extra ocular muscle movement examination of the right eye showed superior, medial, and recti as well as inferior oblique muscle paresis suggestive of a right cranial nerve (CN) III involvement. There was also a right CN VII palsy evidenced by lagopthalmus and facial asymmetry. General neurological examination revealed a left foot drop with the power reduced to 4/5. The reflexes were brisk. All other neurological examinations were normal.Our working diagnosis at that point was an intracranial bleed causing the third and seventh cranial nerve palsies, as well as the motor deficit (foot drop) secondary to the fall. Intracranial space occupying lesion was also on the list of differential diagnosis. CT brain performed on the patient showed an illdefined, minimally enhancing suprasellar mass with specks of calcification within. The mass extended to the posterior fossa, causing mass effect onto the brainstem and obstructive hydrocephalus (Figure 1).The contrasted MRI brain showed an extra-axial lesion at the base of the skull with an epicenter at the sella region. It measured 7.2 × 4.1 × 3.7 cm. The lesion extended postero-inferiorly towards the right pons and midbrain compressing these structures as well as the fourth ventricle. However, no mass was identified within the fourth ventricle itself. It also extended superiorly into the suprasellar region invading the cavernous sinus. It was predominantly solid with several intratumoural cysts seen, largest of which was within the suprasellar component. The lesion was hypointense on T1W and slightly hyperintense on T2W and FLAIR and demonstrated mild restrict...

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Section: Discussionmentioning

confidence: 99%

Medulloblastoma with Suprasellar Extension and Atypical Presentation

et al. 2017

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“…Although medulloblastomas are classically categorized based on the presence of densely packed round cells, pathologic "variants" (large-cell or anaplastic medulloblastoma, desmoplastic medulloblastoma, and medulloblastoma with extensive nodularity) with unique histologic features and biologic or clinical behavior are now recognized and incorporated in the 2007 WHO classification. Investigators have further shown heterogeneous imaging features 46 and marked genetic diversity of medulloblastoma with at least 4 unique molecular subgroups (WNT, SHH, group C, and group D) having distinct transcription profiles, chromosomal aberrations, and clinical behavior. 47,48 Of note, 4 of the 8 medulloblastomas with the highest rTBF (range, 2.16 -4.97) demonstrated the most aggressive behavior, with death occurring within 11 months of tumor diagnosis in 3 patients and the remaining patient classified as having high-risk disease at the time of the study because of leptomeningeal seeding.…”

Section: Discussionmentioning

confidence: 99%

Arterial Spin-Labeled Perfusion of Pediatric Brain Tumors

Yeom¹,

Mitchell²,

Lober³

et al. 2013

American Journal of Neuroradiology

115

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BACKGROUND AND PURPOSE: Pediatric brain tumors have diverse pathologic features, which poses diagnostic challenges. Although perfusion evaluation of adult tumors is well established, hemodynamic properties are not well characterized in children. Our goal was to apply arterial spin-labeling perfusion for various pathologic types of pediatric brain tumors and evaluate the role of arterial spin-labeling in the prediction of tumor grade.

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“…6 Specifically, “tumor location” was defined as midline vermian/fourth ventricle, cerebellar hemisphere, or cerebellar peduncle/cerebellopontine angle cistern (CP/CPA). “Tumor margin” was characterized as ill-defined if >50% of the margin could not be distinguished from the surrounding cerebellar parenchyma on the basis of all imaging sequences.…”

Section: Methodsmentioning

confidence: 99%

“…Prior studies have shown that medulloblastomas present with heterogeneous imaging features, including location and enhancement patterns. 6 These phenotypic radiologic features may reflect underlying differences in tumor biology. 7,8 In this study, we hypothesized that distinct MR imaging features predict molecular subgroups of pediatric medulloblastoma.…”

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confidence: 99%

MRI Surrogates for Molecular Subgroups of Medulloblastoma

Perreault

Ramaswamy

Achrol³

et al. 2014

AJNR Am J Neuroradiol

278

205

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BACKGROUND AND PURPOSE Recently identified molecular subgroups of medulloblastoma have shown potential for improved risk stratification. We hypothesized that distinct MR imaging features can predict these subgroups. MATERIALS AND METHODS All patients with a diagnosis of medulloblastoma at one institution, with both pretherapy MR imaging and surgical tissue, served as the discovery cohort (n = 47). MR imaging features were assessed by 3 blinded neuroradiologists. NanoString-based assay of tumor tissues was conducted to classify the tumors into the 4 established molecular subgroups (wingless, sonic hedgehog, group 3, and group 4). A second pediatric medulloblastoma cohort (n = 52) from an independent institution was used for validation of the MR imaging features predictive of the molecular subtypes. RESULTS Logistic regression analysis within the discovery cohort revealed tumor location (P < .001) and enhancement pattern (P = .001) to be significant predictors of medulloblastoma subgroups. Stereospecific computational analyses confirmed that group 3 and 4 tumors predominated within the midline fourth ventricle (100%, P = .007), wingless tumors were localized to the cerebellar peduncle/cerebellopontine angle cistern with a positive predictive value of 100% (95% CI, 30%–100%), and sonic hedgehog tumors arose in the cerebellar hemispheres with a positive predictive value of 100% (95% CI, 59%–100%). Midline group 4 tumors presented with minimal/no enhancement with a positive predictive value of 91% (95% CI, 59%–98%). When we used the MR imaging feature–based regression model, 66% of medulloblastomas were correctly predicted in the discovery cohort, and 65%, in the validation cohort. CONCLUSIONS Tumor location and enhancement pattern were predictive of molecular subgroups of pediatric medulloblastoma and may potentially serve as a surrogate for genomic testing.

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Distinctive MRI Features of Pediatric Medulloblastoma Subtypes

Abstract: The LC or anaplastic medulloblastoma subtype was associated with increased ADC and with ring enhancement, the latter of which correlated with tumor necrosis. These features could be considered in the evaluation of high-risk medulloblastoma subtypes.

Cited by 102 publications

References 35 publications

Medulloblastoma with Suprasellar Extension and Atypical Presentation

Medulloblastoma with Suprasellar Extension and Atypical Presentation

Arterial Spin-Labeled Perfusion of Pediatric Brain Tumors

MRI Surrogates for Molecular Subgroups of Medulloblastoma

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