title: Inverted papilloma invading the orbit through the nasolacrimal duct: a case report.
abstract: OBJECTIVE
  Inverted papillomas of the nose and paranasal sinuses are uncommon neoplasms, characterized by their tendency to recur and by their association with malignancy and invasive potential to the adjacent structures. The authors report a case of recurrent inverted papilloma of the nasal cavity and sinuses that eventually invaded the orbit through the nasolacrimal duct.
  
  
  METHODS
  Assessment and management of a 47-year-old patient who presented with epiphora, left medial canthal area mass, proptosis and lateral displacement of his left eye associated with significant nasal obstruction.
  
  
  RESULTS
  Computed tomography and magnetic resonance imaging studies revealed a mass filling the nasal cavities and sinuses, invading the left orbit without destruction of any orbital walls. During excision of the tumor, it was learned that the orbital component of the tumor was connected with the sinonasal tumor through the nasolacrimal duct without any bony defects of the orbit. Histopathology of tumor proved to be inverted papilloma with areas of malignant transformation.
  
  
  CONCLUSIONS
  Athough a rare cause of proptosis, inverted papilloma with orbital invasion must be considered in the differential diagnosis of nasosinus tumors invading the orbit. The case presented demonstrates that these tumors may invade the orbit through the nasolacrimal duct in the absence of orbital wall defects.
authors.affiliation: Oculoplastic and Orbit Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. orbitdr@hotmail.com
authors.forename: Imtiaz A
authors.initials: IA
authors.lastname: Chaudhry
authors.forename: Khalid
authors.initials: K
authors.lastname: Taiba
authors.forename: Yasir
authors.initials: Y
authors.lastname: Al-Sadhan
authors.forename: Fenwick C
authors.initials: FC
authors.lastname: Riley
mesh_terms: D006801:Humans; D008297:Male; D008875:Middle Aged; D009301:Nasolacrimal Duct; D009361:Neoplasm Invasiveness; D009669:Nose Neoplasms / Q000150:complications* / Q000473:pathology; D013508:Ophthalmologic Surgical Procedures; D009918:Orbital Neoplasms / Q000209:etiology* / Q000473:pathology; D018308:Papilloma, Inverted / Q000209:etiology* / Q000473:pathology; D011878:Radiotherapy