Pneumocephalus from a frontal-ethmoid neurilemoma.

A 68-year-old man had memory lapse, character change, and unsteady gait. Skull films disclosed a spontaneous pneumocephalus with air in both ventricles. A dense, bony lesion in the right ethmoid area was thought to be an osteoma, a not infrequent cause of dural erosion. The bony lesion, however, proved to be an osteoid reaction around a primary neurilemoma. Neurilemomas arising in the paranasal sinuses are uncommon tumors and, to the best of our knowledge, this is the first reported case of a patient with a neurilemoma who had pneumocephalus. The lesion was excised through a Lynch approach, and the patient has remained free of tumor for the past two years.