Classification Systems Of Glomus Tumors

Two contemporary anatomically based classification systems of glomus tumors are commonly cited. The first is the four-tiered grouping of Oldring and colleagues37 of Zurich, first reported in 1979 and subsequently revised in later reports (Table 82-1). The second is the classification initially described in 1982 by Glasscock and Jackson39 of the Otology Group in Nashville. The latter classification divides glomus tumors into two main groups, glomus jugulare tumors and glomus tympanicum tumors. Each of these two main groups is further subdivided into four subgroups (Table 82-2). These classification systems serve as the standard language by which

TABLE 82-2

Glasscock-Jackson Classification of Glomus Tumors*

TABLE 82-2

Glasscock-Jackson Classification of Glomus Tumors*

Type

Description

A.

Glomus tympanicum

I Small promontory mass

II Fills middle ear

III Fills middle ear and extends into mastoid

IV Extends into external auditory canal, with or

without extension to ICA

B.

Glomus jugulare

I Small, jugular bulb, middle ear, mastoid

II Extends under IAC, with or without intracranial

extension

III Extends to petrous apex, with or without

intracranial extension

IV Beyond petrous apex to clivus or infratemporal

fossa, with or without intracranial extension

*From Glasscock et al.39

*From Glasscock et al.39

these lesions can be described. In addition, preoperative grading of glomus tumors that use these classification schemes and preoperative imaging studies has been shown to be a useful guide for choosing the appropriate surgical approach. Finally, the preoperative grade of the tumor according to these classification systems correlates with the likelihood of attaining a complete surgical resection and as a predictor of postoperative CN morbidity.14

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