Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
March 2018
Next Case Coming April 3...
Intraparenchymal Thalamic Epidermoid Cyst
- Background:
- Epidermoid cysts can be congenital or acquired.
- Intracranial epidermoid cysts are typically thought to arise from ectodermal inclusions trapped during the closure of the neural tube in the 3–5 weeks of embryogenesis.
- Intraparenchymal epidermoid cysts are rare, with around 60 cases described in the literature.
- There are rare (~3) reports of intrathalamic cysts.
- There are rare (~3) reports of intrathalamic cysts.
- Imaging Findings:
- T2 hyperintense; usually hyperintense to CSF on FLAIR; nonenhancing (if not inflamed or infected); marked restricted diffusion
- Case reports of MRS have all described large lactate peaks and absent NAA peaks (consistent with lack of neural tissue).
- Grow slowly if followed over time
- Differential Diagnosis:
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Arachnoid cyst: should follow CSF intensity on all sequences
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Low-grade tumor: will usually enhance and not demonstrate such avid restricted diffusion
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Dermoid cyst: usually more fat signal and less/no restricted diffusion
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Abscess: will elicit extensive surrounding edema and have an enhancing capsule
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Treatment:
- Surgical excision
- Can recur if incompletely excised