September 2017
A previously healthy 6-year-old boy with 1 month of early morning vomiting and headache
Atypical Teratoid/Rhabdoid Tumor (AT/RT), WHO grade IV
- Background:
- Highly malignant, uncommon CNS tumor usually affecting patients <3 years of age
- 1–2% of all pediatric CNS malignancy
- Most common CNS tumor in children <6 months of age
- Patients present with signs of increased intracranial pressure, headache, and cranial nerve palsies in posterior fossa.
- Distinction from medulloblastoma and PNET has been historically difficult.
- Presence of rhabdoid cells on pathology and loss of normal INI1 or BRG1 staining is key to pathologic diagnosis.
- Should consider for any large, heterogeneous/necrotic intracranial tumor in patient <3 years old
- Imaging Characteristics:
- Heterogeneous mass with mixed cystic and solid components, often hyperdense on CT, hypointense/heterogeneous on T2, heterogeneous enhancement, may contain hemorrhage or Ca++
- Often hyperintense on DWI due to increased cellularity
- Calcifications seen in up to 40%
- Fairly even split between posterior fossa and supratentorial region (roughly 40–45% each), both in ~10%
- Propensity for leptomeningeal metastases, so entire spine imaging preoperative is required
- DDX:
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Medulloblastoma/PNET
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Primary ddx, can be indistinguishable on imaging
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Keys to differentiate: AT/RT more likely in younger patients (<3 years), more likely to be off-midline, more likely to contain cysts, calcification and hemorrhage
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Ependymoma
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High-grade glioma
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- Treatment:
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Optimal management is maximal safe resection followed by radiation and intensive chemotherapy
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