Slow-growing WNT medulloblastoma with atypical magnetic resonance imaging findings: illustrative case
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Updated: Jul 16, 2025
Isolation, Enrichment, and Maintenance of Medulloblastoma Stem Cells
Published on: September 1, 2010
Makoto Mizushima1, Michinari Okamoto1, Shigeru Yamaguchi1
11Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Background:
Medulloblastomas, with four molecular subgroups, are generally rapid-growing tumors with significant contrast enhancement and well-defined margins. However, each subgroup's clinical features, including disease time course and imaging characteristics, are not well defined.
Observations:
The authors describe the case of a 15-year-old female who presented with a 7-month history of impaired left-hand movement and was found to have a lesion on the dorsal side of the fourth ventricle. T2-weighted magnetic resonance imaging (MRI) at the patient's first presentation showed diffuse hyperintense signal without apparent mass, and gadolinium-enhanced T1-weighted imaging showed very slight contrast enhancement. In 1 month, her symptoms progressed, and follow-up MRI revealed an increase in the size of the lesion, showing greater diffusion restriction and contrast enhancement. She underwent gross-total resection, and pathology was consistent with classic medulloblastoma. Genetic analysis of the tumor confirmed the wingless (WNT) molecular subgroup. Adjuvant chemotherapy and proton beam therapy were performed. At the 18-month follow-up, MRI showed no recurrence of disease.
Lessons:
Slow-growing medulloblastoma is very rare and not known to be associated with a specific molecular subgroup. Here, the authors report a case of slow-growing WNT medulloblastoma, indicating that slow growth may be a feature of this subgroup.
Insights
This study reports a rare case of slow-growing medulloblastoma in a WNT molecular subgroup. This finding suggests that slow growth may be a characteristic feature of this specific medulloblastoma subgroup.
Area of Science:
- Neuro-oncology
- Molecular Subtyping of Tumors
- Pediatric Oncology
Background:
- Medulloblastomas are typically rapid-growing brain tumors with four distinct molecular subgroups.
- Clinical features and disease progression vary among medulloblastoma subgroups.
- Imaging characteristics of medulloblastoma subgroups are not fully elucidated.
Purpose of the Study:
- To present a rare case of slow-growing medulloblastoma.
- To investigate the clinical and imaging features of a WNT subgroup medulloblastoma.
- To explore potential associations between slow tumor growth and specific molecular medulloblastoma subgroups.
Main Methods:
- Case report of a 15-year-old female with a 7-month history of neurological symptoms.
- Magnetic resonance imaging (MRI) including T2-weighted and gadolinium-enhanced T1-weighted sequences.
- Tumor resection, histopathological analysis, and molecular subtyping (WNT subgroup confirmation).
Main Results:
- Initial MRI showed a subtle lesion with minimal contrast enhancement, progressing over one month with increased size, diffusion restriction, and enhancement.
- Pathology confirmed classic medulloblastoma, genetically classified as the WNT subgroup.
- The patient achieved complete remission after gross-total resection, adjuvant chemotherapy, and proton beam therapy, with no recurrence at 18 months.
Conclusions:
- Slow-growing medulloblastoma is exceptionally rare and not previously linked to a specific molecular subgroup.
- This case highlights a slow-growing WNT medulloblastoma, suggesting slow growth could be a characteristic of this subgroup.
- Further research is warranted to confirm slow growth as a feature of WNT medulloblastoma.
