Glasscock-Jackon classification

Glomus jugulare tumors

Grade I

Small tumor involving jugular bulb, middle ear, and mastoid

Grade II

Tumor extending under internal auditory canal; may have intracranial extension

Grade III

Tumor extending into petrous apex; may have intracranial extension

Grade IV

Tumor extending beyond petrous apex into clivus or infratemporal fossa; may have intracranial extension

Reference

Michael LM, Robertson JH. Glomus jugulare tumors: historical overview of the management of this disease. Neurosurg Focus 2004; 17:E1.