Glomus Tympanicum

The Glasscock and Jackson’s system

Type 1 Glomus tumours are limited to the promontory,

Type 2 Denotes tumour completely filling the middle ear.

Type 3 Indicates tumour extending further into mastoid,

Type 4 Glomus tumours spread into external auditory canal and may have intracranial extension.

The Fisch classification of glomus tumors is based on extension of the tumor to surrounding anatomic structures and is closely related to mortality and morbidity.

• Type A tumor - Tumor limited to the middle ear cleft (glomus tympanicum)
• Type B tumor - Tumor limited to the tympanomastoid area with no infralabyrinthine compartment involvement
• Type C tumor - Tumor involving the infralabyrinthine compartment of the temporal bone and extending into the petrous apex 
• Type D tumor - Tumor with an intracranial extension