Frontal sinus osteoma with complicating intracranial aerocele.

An elderly man, who presented initially with clinical features of dementia, was found to have an intracranial tension aerocele due to an underlying osteoma of the frontal sinus. Plain skull roentgenograms and computerized tomography did not reveal the osteoma, although a communication between the frontal sinus and the aerocele was present. Surgical aspiration of the aerocele and excision of the osteoma produced an excellent clinical result.