Haemosiderin cap sign

Dr Dan J Bell and 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 haemangioblastomas 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 haemosiderin ring where they reach the pial surface, and thus develop a haemosiderin cap. 

Share article

Article information

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

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1: ependymoma
    Drag here to reorder.
  • Drag
    Case 2: paraganglioma
    Drag here to reorder.
  • Drag
    Case 3: cavernoma
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.