title: Imaging findings of parapharyngeal space pleomorphic adenoma in comparison with parotid gland pleomorphic adenoma.
abstract: OBJECTIVE
  The purpose of this study was to assess imaging findings of parapharyngeal space (PPS) pleomorphic adenoma (PA) in comparison with parotid gland (PG) PA retrospectively.
  
  
  METHODS
  Ten patients with PPS PAs and 66 with PG PAs were included. CT and MR images were reviewed for the size, presence of calcification or cystic degeneration, and MR signal intensity of solid components.
  
  
  RESULTS
  The maximum diameter was greater in PPS PA (57.3 ± 11.4 mm) than in PG PA (28.7 ± 20.8 mm) (p < 0.01). The frequency of calcification was higher in PPS PA (50 %) than in PG PA (15 %) (p < 0.05). The frequency of cystic degeneration was marginally higher in PPS PA (60 %) than in PG PA (29 %) (p = 0.058). On T2-weighted images, solid components of PPS and PG PAs showed hyperintensity in 40 and 54 %, isointensity in 50 and 32 %, and hypointensity in 10 and 14 %, respectively.
  
  
  CONCLUSIONS
  The size and the frequency of calcification or cystic degeneration were higher in PPS PAs than in PG PAs. Radiologists should recognize the difference in imaging features between PPS and PG PAs.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan, hkato@gifu-u.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanematsu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mizuta
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Aoki
mesh_terms: D008949:Adenoma, Pleomorphic / Q000175:diagnosis* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019647:Oral Surgical Procedures / Q000379:methods; D010307:Parotid Neoplasms / Q000175:diagnosis* / Q000601:surgery; D010610:Pharyngeal Neoplasms / Q000175:diagnosis* / Q000601:surgery; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome