title: Atypical sinonasal Schwannomas: a difficult diagnostic challenge.
abstract: OBJECTIVE
  Schwannomas are benign tumours arising from Schwann cells of the peripheral nerve sheath. They are relatively frequent in the head and neck region (25-45%) but rarely involve in the sinonasal tract (4%). The authors outline the diagnostic difficulties and the problems in choosing the best surgical approach in two atypical cases of sinonasal Schwannomas.
  
  
  METHODS
  In the first case reported clinical data, sex and age of the patient, nasal endoscopy and angio-MRI led us to suspect an angiofibroma; therefore, we approached the case without a biopsy performing a preoperative selective embolization followed by an endoscopic resection. In the second case, due to initial visual symptoms and to the ethmoid-orbital compartment involvement, we performed a sinonasal endoscopy and collected a biopsy which resulted to be fundamental in the diagnostic assessment. Tumour excision was then obtained throughout an intracranial/endonasal approach.
  
  
  RESULTS
  The two presented cases revealed the presence of cystic Schwannomas. In the first case, diagnosis was made only post-operatively after histological examination. Patients underwent complete surgical excision by means of an endoscopic sinonasal approach, in the second case associated to a left frontal craniotomy. The patients showed no signs of recurrence at a 9 months follow-up.
  
  
  CONCLUSIONS
  Nasal endoscopy was extremely important in making the diagnosis, allowing an accurate assessment of the tumour extension and a biopsy. The diagnosis of sinonasal Schwannomas remains challenging; sometimes, clinical behaviour and modern imaging may be misleading. The diagnostic and therapeutic importance of sinonasal endoscopy is emphasised in the two presented cases.
authors.affiliation: Institute of Otorhinolaryngology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Galli
authors.initials: G
authors.lastname: Jacopo
authors.forename: Imperiali
authors.initials: I
authors.lastname: Micaela
authors.forename: Cantore
authors.initials: C
authors.lastname: Italo
authors.forename: Corina
authors.initials: C
authors.lastname: Luigi
authors.forename: Luigi M
authors.initials: LM
authors.lastname: Larocca
authors.forename: Paludetti
authors.initials: P
authors.lastname: Gaetano
mesh_terms: D001706:Biopsy; D003287:Contrast Media; D003560:Cysts / Q000175:diagnosis; D003937:Diagnosis, Differential; D004724:Endoscopy; D006801:Humans; D007150:Immunohistochemistry; D018810:Magnetic Resonance Angiography; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000175:diagnosis* / Q000601:surgery; D009669:Nose Neoplasms / Q000175:diagnosis* / Q000601:surgery; D009918:Orbital Neoplasms / Q000175:diagnosis* / Q000601:surgery; D010255:Paranasal Sinus Neoplasms / Q000175:diagnosis* / Q000601:surgery; D055815:Young Adult
chemical_list: D003287:Contrast Media