Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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September 20, 2010
Myxopapillary Sacrococcygeal Ependymoma
- Ependymomas rarely occur outside the CNS. Of those that do, the majority are in the sacrococcygeal or presacral areas.
- Primary subcutaneous extraneural sacrococcygeal ependymomas are thought to arise from ependymal rests or from the coccygeal medullary vestige, an ependymal lined remnant at the caudal portion of the neural tube.
- Up to 20% develop distant metastasis, which can occur as late as 20 years after original presentation. Therefore, long-term follow-up is necessary.
- The subcutaneous sacrococcygeal ependymomas grow slowly and usually present as large masses.
- They are generally encapsulated with a firm/rubbery texture.
- Key Diagnostic Features: Imaging appearances vary as they are often complicated by hemorrhage, necrosis and may have areas of fibrosis and calcification, which produces a heterogenous appearance on all MR sequences.
- DDx: Although appearances mimic those of teratoma, sacrococcygeal teratomas are more common in the newborn. Differential diagnoses in an adult include pilonidal cyst and neurogenic tumors.