Extracranial, extraspinal meningiomas of the head and neck.

The head and neck is the most frequent location for extraneuraxial meningiomas, be they wholly extracranial or extraspinal or extensions of central nervous system meningiomas. Regardless of anatomic site of origin, nearly all meningiomas arise from meningocytes of arachnoid granulations. Ectopic arachnoid cell clusters have a predilection for areas of dural penetration of cranial nerves, and it is in these areas that most extracranial meningiomas are found. Surgical excision is the mainstay of treatment and must be planned by radiologic studies to determine the extent of the tumor and the presence or absence of a companion central nervous system meningioma. The often locally invasive and aggressive behavior of the meningiomas belies their benign histologic appearance.