title: Orbital neurofibroma presenting with a negative Hounsfield unit on computerized tomography.
abstract: OBJECTIVE
  To report a case of diffuse orbital neurofibroma which displayed an unusual computed tomography (CT) feature.
  
  
  METHODS
  Results of ocular examination, orbital CT examination and pathological findings in a patient with a space-occupying orbital lesion are presented.
  
  
  RESULTS
  Orbital CT evaluation of a male patient, aged one and a half years old, revealed a right orbital lesion with a strongly negative value in Hounsfield units. The preoperative diagnosis was a dermoid cyst. An anterior orbitotomy was performed, and the surgical specimen demonstrated a typical plexiform neurofibroma with routine hematoxylin and eosin staining and immunohistochemical studies.
  
  
  CONCLUSIONS
  Plexiform orbital neurofibromas may demonstrate a negative Hounsfield value on CT examination.
authors.affiliation: Zhongshan Ophthalmic Center, the Section of Ocular Oncology & Orbital Disease, Sun Yat-sen University, Guangzhou, People's Republic of China. Yan2011@tom.com
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yan
authors.forename: Yongping
authors.initials: Y
authors.lastname: Li
authors.forename: Zhongyao
authors.initials: Z
authors.lastname: Wu
mesh_terms: D003884:Dermoid Cyst / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D008297:Male; D009455:Neurofibroma / Q000000981:diagnostic imaging* / Q000473:pathology; D018318:Neurofibroma, Plexiform / Q000000981:diagnostic imaging* / Q000473:pathology; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed