title: Benign mass lesions deep inside the temporal bone: imaging diagnosis for proper management.
abstract: CONCLUSIONS
  Among mass lesions inside the temporal bone, benign tumors and cholesteatomas can be differentiated by contrast enhancement in T1-weighted images (T1WI) and by diffusion-weighted images (DWI). Moreover, DWI will also facilitate discrimination between cholesteatomas accompanied by granulation and other non-neoplastic lesions such as mucoceles and cholesterol granulomas.
  
  
  OBJECTIVE
  To review the imaging characteristics of mass lesions inside the temporal bone and to investigate pertinent imaging modalities for differential diagnosis, which is crucial for appropriate treatment planning.
  
  
  METHODS
  This was a retrospective case series study of six patients seen between 2002 and 2005 with mass lesions deep inside the temporal bone.
  
  
  RESULTS
  One patient had facial schwannoma, two had glomus jugulare tumor, and three had cholesteatoma. Plain high resolution CT gave few clues to the nature of the mass lesions. MRI study provided us with better clues: contrast enhancement on T1WI was observed only in benign tumors and only cholesteatomas showed high intensity on DWI. With the assistance of neurosurgeons, surgery was successfully performed in all cases.
authors.affiliation: Department of Otolaryngology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Okada
authors.forename: Ken
authors.initials: K
authors.lastname: Ito
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
authors.forename: Megumi
authors.initials: M
authors.lastname: Ishii
authors.forename: Shinichi
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Kaga
mesh_terms: D000792:Angiography; D018424:Cholesteatoma, Middle Ear / Q000150:complications / Q000175:diagnosis / Q000601:surgery; D003390:Cranial Nerve Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005154:Facial Nerve / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005925:Glomus Jugulare Tumor / Q000175:diagnosis*; D006099:Granuloma / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009078:Mucocele / Q000175:diagnosis*; D009442:Neurilemmoma / Q000175:diagnosis* / Q000601:surgery*; D013701:Temporal Bone / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed