Intraosseous pneumatocyst

Intraosseous pneumatocysts are gas-containing cystic structures seen inside the bone.

They are of uncertain aetiology. These cysts do not communicate with the joint.

Most common site of involvement is sacroiliac joints. Other sites involved are cervical spine, scapula and other bones rarely.

Appear as very low density (i.e. air at approximately -1000 HU) cystic lesion with thin sclerotic margin, usually abutting a joint.

Low signal intensity on both T1 and T2 weighted MR images. 

Imaging differential considerations include

  • There is a risk of erroneously misdiagnosing intraosseous lipomas as intraosseous pneumatocysts, or vice-versa, if the lesion is only eye-balled on a soft tissue window. Therefore if unsure, one should either measure an ROI of the lesion to clarify if gas or fat density, or review the lesion on a lung window.
Share article

Article information

rID: 26155
Tag: cases
Synonyms or Alternate Spellings:
  • Intraosseous pneumatocysts
  • Intra-osseous pneumatocyst
  • Intra-osseous pneumatocysts

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1
    Drag here to reorder.
  • Drag
    Case 2: Intraosseous pneumatocyst
    Drag here to reorder.
  • Drag
    Intraosseous pneu...
    Intraosseous pneumatocyst
    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.