Pediatric Arrested Pneumatization of the Skull Base

  • Etiology: Developmental variant where sinus aeration process fails to fully replace sites of fatty converted marrow
  • Imaging:
    — Usually around formen rotundum or vidian canal
    — Occurs at sites of normal or accessory pneumatization – usually sphenoid sinus but also basisphenoid or pterygoids or anterior clinoids or clivus or multiple contiguous sites
    — Non aggressive appearance
  • Imaging CT:
    — Respects foramen
    — Narrow and osteosclerotic borders
    — No destruction or occlusion (as in fibrous dysplasia)
    — Nonexpansile (as opposed to fibrous dysplasia)
    — Curvilinear calcifications (not ground glass as in fibrous dysplasia)
  • Imaging MRI:
    — Fat and soft tissue signal intensity which is interspersed
    — Fatty component usually brighter than normal marrow
  • DDX: Fibrous dysplasia which has expansile and ground glass appearance and causes destruction or occlusion
  • Complications: None
  • Treatment: None
  • Clinical:

Radiology Cases of Arrested Pneumatization of the Skull Base

MRI and CT of arrested pneumatization of the skull base
Axial T1 MRI without contrast of the brain (above left) shows an isointense signal intensity lesion in the right sphenoid bone that on T2 MRI (above right) shows a high signal intensity and which did not show enhancement post contrast. The remaining paranasal sinuses are clear. Coronal CT without contrast of the maxillofacial bones (below) shows the right sphenoid bone to be filled with a lucent non-expansile and non-destructive lesion.