Nonneoplastic or metabolic disease
Hyperostosis cranii ex vacuo

Topic Completed: 1 June 2012

Minor changes: 5 July 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Hyperostosis cranii ex vacuo

Dariusz Borys, M.D.
Page views in 2019: 243
Page views in 2020 to date: 84
Cite this page: Borys D. Hyperostosis cranii ex vacuo. website. Accessed June 3rd, 2020.
Definition / general
  • Also called thickened calvarium
  • May be due to intracranial hypotension associated with chronic shunting, as skull lacks the outward pressure needed to expand (Hum Pathol 1994;25:545)
Case reports
Gross description
  • Circumferentially thickened skull, particularly inner table, involvement of calvarium and base
Gross images

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Thickened skull

Microscopic (histologic) description
  • Increased cancellous space with normal trabecular bone
Microscopic (histologic) images

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Figure 2B-increased cancellous space

Differential diagnosis
  • Paget’s disease, fibrous dysplasia, thalassemia, hyperostosis frontalis interna (inner table has varying thickness of lobulated bone)
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