Yonsei Med J.  1998 Apr;39(2):148-153. 10.3349/ymj.1998.39.2.148.

Facial nerve schwannomas: CT and MR findings

• Chung SY
• Kim DI
• Lee BH
• Yoon PH
• Jeon P
• Chung TS

• KMID: 711539
• DOI: http://doi.org/10.3349/ymj.1998.39.2.148

Abstract

The present study was undertaken to analyze the radiologic findings of intratemporal and extratemporal schwannoma (ITS & ETS). We retrospectively reviewed the CT (9 cases), MR (3 cases) and medical records of 10 facial schwannoma patients. After classifying these into ITS and ETS, radiologic and clinical findings were analyzed. The most common clinical manifestations were facial nerve dysfunction (6/6 cases, 100%) and hearing impairment (5/6 cases, 83.3%) in ITS and parotid mass (4/4 cases, 100%) in ETS. Geniculate ganglion (GG) was the most commonly involved segment of ITS (5/6 cases, 83.5%). On CT, ITS arising in GG (4 cases) showed erosion of the petrous bone (4 cases), cochlea (3 cases), lateral semicircular canal (1 case) and ossicles (3 cases). ITS arising in the mastoid segment (1 case) showed the destruction of the jugular plate and external auditory canal wall. All three ITS in which MRI was performed showed iso- to hypointensity on T1WI, hyperintensity on T2WI and well-enhanced on post-enhanced T1WI. ETS showed various findings, but all four ETS were located in the posterolateral portion of the retromandibular vein and extended toward the stylomastoid foramen. In conclusion, ITS shows the schwannoma on MR. ETS shows various findings. However, if the tumor is located along the extratemporal facial nerve course, then facial schwannoma may be suspected.

Keyword

Schwannoma; facial nerve; CT; MR

MeSH Terms

Adult
Cranial Nerve Neoplasms/diagnosis*
Facial Nerve*
Female
Geniculate Ganglion/radiography
Geniculate Ganglion/pathology
Human
Magnetic Resonance Imaging*
Male
Middle Age
Neurilemmoma/diagnosis*
Tomography, X-Ray Computed*