Advanced pneumatization of the mastoid process

What it means

An abnormally advanced degree of pneumatization (i.e., formation of air cells) in the mastoid process with respect to age-dependent norms.

Rare diseases that can present with this1

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category