title: Case of malignant transformation of vagus nerve schwannoma to angiosarcoma.
abstract: BACKGROUND
  It is known that benign tumors have the potential for malignant transformation. Malignant transformation of vagus nerve schwannoma to angiosarcoma is very rare.
  
  
  METHODS
  We report a case of malignant transformation in which the initial diagnosis was subsequently altered to angiosarcoma originating from the vagus nerve. We compared the findings of MRI and fine-needle aspiration (FNA) at initial diagnosis with those after malignant transformation.
  
  
  RESULTS
  MRI revealed that the mass property had been changed from the initial tumor; also the FNA findings were significantly different from those in the previous ones. The patient had significant clinical progression with multiple cranial neuropathies and died.
  
  
  CONCLUSIONS
  Schwannomas sometimes undergo malignant transformation; therefore, surgery should be recommended. If follow-up observation is chosen, MRI and FNA should be regular and patients should sign a statement acknowledging awareness of the potential for malignant transformation.
authors.affiliation: Department of Otorhinolaryngology, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ogawa
authors.forename: Takashige
authors.initials: T
authors.lastname: Kato
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Ikeda
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Nishimura
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Hiroki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Emiko
authors.initials: E
authors.lastname: Takahashi
authors.forename: Toyoharu
authors.initials: T
authors.lastname: Yokoi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ueda
mesh_terms: D044963:Biopsy, Fine-Needle; D002471:Cell Transformation, Neoplastic; D003390:Cranial Nerve Neoplasms / Q000473:pathology*; D018450:Disease Progression; D017809:Fatal Outcome; D006394:Hemangiosarcoma / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009442:Neurilemmoma / Q000473:pathology*; D020421:Vagus Nerve Diseases / Q000473:pathology*
keywords: MRI; angiosarcoma; fine-needle aspiration; malignant transformation; schwannoma