title: Ethmoidal air cell schwannoma presented as a fronto-ethmoidal mucocele.
abstract: OBJECTIVE
  To report a rare case of a fronto-ethmoidal mucocele secondary to an ethmoidal schwannoma. To our knowledge this is the first reported case of an ethmoidal schwannoma, a tumour of the peripheral nerve sheath originating from an area not believed to contain peripheral nerves that has presented as a fronto-ethmoidal mucocele.
  
  
  METHODS
  Our patient is a 23-year-old male presented with a one-year history of progressive proptosis and vertical diplopia with restriction of upgaze. Orbital imaging demonstrated a mass in the right medial ethmoidal air cells extending to the frontal sinus and orbit, consistent with a mucocele. Patient underwent endonasal decompression of the right fronto-ethmoidal mucocele. Histology confirmed a schwannoma and repeat imaging post-operatively revealed residual mass originating from the ethmoidal air cells. A right upper eyelid skin crease approach anterior orbitotomy was performed to successfully excise the mass via the lamina papyracea. Post-operatively the patient's proptosis and diplopia resolved, with a full range of ocular movements. Post-operative imagining at 3 months did not show any residual tumour.
  
  
  CONCLUSIONS
  Mucocele formation may be secondary to an underlying schwannoma obstructing the fronto-ethmoidal foramen. In such cases we recommend an open-sky technique for full visualisation and improved chance of total removal.
authors.affiliation: Department of Ophthalmology, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, Norfolk, United Kingdom.
authors.forename: Ramy
authors.initials: R
authors.lastname: Bassily
authors.forename: Daniel
authors.initials: D
authors.lastname: Wallace
authors.forename: Vasilis
authors.initials: V
authors.lastname: Liolios
authors.forename: Peter
authors.initials: P
authors.lastname: Prinsely
authors.forename: Bijan
authors.initials: B
authors.lastname: Beigi
mesh_terms: D019299:Decompression, Surgical; D005005:Ethmoid Sinus / Q000473:pathology*; D005094:Exophthalmos / Q000209:etiology* / Q000473:pathology / Q000601:surgery*; D005626:Frontal Sinus / Q000473:pathology*; D006801:Humans; D008297:Male; D009078:Mucocele / Q000209:etiology* / Q000473:pathology / Q000601:surgery*; D009442:Neurilemmoma / Q000150:complications* / Q000473:pathology / Q000601:surgery*; D010255:Paranasal Sinus Neoplasms / Q000150:complications* / Q000473:pathology / Q000601:surgery*; D055815:Young Adult