Traumatic subperiostial emphysema caused by hyperpneumatization of the temporal and occipital bone.

Hyperpneumatization of the temporal bone with extension into the occipital bone and even the parietal bones is a rare condition. We report a case in which the patient suffered periodically from a palpable mass in the parietal-occipital region which originated from extensive occipital bone pneumatization. Computed tomography examination revealed extensive temporal and occipital pneumatization and subperiosteal pneumatoceles, which was corrected by surgery.