Haemosiderin cap sign

The haemosiderin cap sign refers to an MR imaging feature in some spinal tumours where a cap of T2 hypointense haemosiderin is above and/or below the tumour due to previous haemorrhage. 

It is most often associated with spinal cord ependymomas (20-33% of cases) 1. It may also be seen in haemangioblastomas and paragangliomas and therefore it is suggestive  but not pathognomonic of ependymoma

In addition, larger cavernous malformations of the spine may appear to lack a complete haemosiderin ring where they reach the pial surface, and thus develop a haemosiderin cap. 

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Article information

rID: 20206
Section: Signs
Tags: refs, spine
Synonyms or Alternate Spellings:
  • Cap sign of spinal tumour
  • Hemosiderin cap sign

Cases and figures

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    Case 1: ependymoma
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    Case 2: paraganglioma
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    Case 3: cavernoma
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