What Are Skull Base Tumors?

Doctor feeling patient nodes under neck, cranial base tumors

Skull base tumors, sometimes called cranial base tumors, are tumors that form at the base of the skull or spread to that location from a cancer elsewhere in the body. Northwestern Medicine treats all types of skull base tumors including:

  • Acoustic neuroma: This is a rare, usually benign tumor of the auditory nerve, the nerve that connects the ear to the brain. Symptoms include hearing loss, tinnitus, dizziness and paralysis of the facial nerves. Acoustic neuromas can also be called vestibular schwannoma or cranial nerve schwannomas.
  • Arachnoid cysts: These are small, fluid-filled sacs that appear—usually from birth—in the tissue surrounding the cranial nerves. Symptoms include headaches, seizures, developmental delay and visual problems.
  • Carotid body tumor (chemodectomas or paraganglioma): This is an often-aggressive tumor growing next to the branching of the carotid artery in the upper neck. Removal may also involve a vascular surgeon to bypass or repair damage to the carotid artery.
  • Cholesterol granuloma: This is a rare, slow-growing cyst near the middle ear that contains crystallized cholesterol and fat. Granulomas are associated with bleeding and the body’s inflammatory response to cholesterol in the blood. Left untreated, they can cause nerve damage and hearing loss.
  • Chordoma: This is a rare, benign tumor that grows in the base of the skull, slowly putting pressure on the nerves that affect vision and hearing.
  • Ear cancer: Ear cancer is a general term that refers to several types of cancers that affect the ear canal or middle ear, often beginning as squamous cell carcinomas. Treatment can include surgery, radiation and chemotherapy.
  • Epidermoid tumors: These are present at birth but grow so slowly that they do not cause symptoms until adulthood. Because they often appear close to the brain stem, epidermoid tumors can affect breathing, heart rate, blood pressure and other essential functions.
  • Glomus jugulare: These tumors grow where the jugular vein and cranial nerves exit the skull near the temporal bone. Symptoms can include hearing problems, difficulty swallowing, hoarseness and paralysis of a facial nerve.
  • Glomus tympanicum (parangangliomas of the middle ear): These are usually benign tumors that cause hearing loss, tinnitus, vertigo and paralysis of a facial nerve. These tumors can be filled with blood vessels that are observed as a red mass behind the eardrum.
  • Meningiomas: Meningiomas are common brain tumors that grow in the tissue between the skull and the brain. Skull base meningiomas form at the bottom of the skull or the bony ridge at the back of the eyes.
  • Neurofibromatosis type 2 (NF2): This is a genetic condition that predisposes carriers to develop acoustic neuromas and other tumors in the nerves of the head and spinal cord, leading to hearing and vision problems.
  • Petrous apex cysts: These are fluid-filled sacs that occur in the skull next to the inner ear, causing ringing of the ears or hearing loss. Most petrous apex cysts are benign, but lesions may metastasize in this part of the brain from cancers in other parts of the body.
  • Posterior fossa cysts: These are fluid-filled sacs that appear in the compartment or sinus at the base of the skull.