Intracranial extension of nasal dermoids.

Nasal dermoid cysts with intracranial extension have been thought to be a rare entity. Seven new cases of nasal dermoid cyst with intracranial involvement were treated from 1975 through 1982 by combined otolaryngological-neurosurgical management. Preoperative radiological studies were helpful in predicting intracranial extension in only three cases. The extracranial lesion was resected by the otolaryngologist using surgical hemoclips to tag the dermoid remnant entering the cranium. These hemoclips were a helpful landmark for the neurosurgeon when resecting the intracranial extension through a bifrontal craniotomy approach. In four cases, the dermoid cyst entered the cranium through a persistent foramen cecum and lay within the falx in association with a bifid crista galli. We think that this entity is more common than was previously appreciated. Patients with a diagnosis of nasal dermoid should undergo polytomography or computed tomography of the glabellar area. Even when all x-ray studies are negative, neurosurgical preoperative evaluation and operative standby should be obtained before the otolaryngologist attempts the resection of a nasal dermoid cyst.