The most common causes of intracranial air are head trauma and neurosurgical procedures. Less common etiologies include infection due to gas-forming organisms, mucoceles, tumours, congenital neuroenteric cysts, and dural defects. Here, we present a case of a frontal sinus osteoma associated with longstanding pneumocephalus.

Keywords: osteoma, paranasal sinuses, pneumocephalus, imaging