Haemosiderin cap sign

Dr Andrew Dixon et al.

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, being seen in 20-33% of these cases 1. The sign, however, may also be seen in hemangioblastomas and paragangliomas and therefore it is suggestive of but not pathognomonic for ependymoma

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

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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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