The layer cake skull refers to the appearance of diffuse calvarial hyperostosis in a distinct concentric pattern deep to the inner table of the skull. It is a relatively common imaging finding in patients with spontaneous intracranial hypotension seen in up to 14% of patients according to a large retrospective study 1.
It is hypothesized that hyperostosis occurs due to chronic loss of CSF thus it is more likely to be seen in long-standing intracranial hypotension.