title: Necrotizing sialometaplasia of the lacrimal sac mimicking squamous cell carcinoma: Necrotizing dacyocystometaplasia.
abstract: BACKGROUND
  Necrotizing sialometaplasia is thought to represent an inflammatory reaction directed against an ischemic insult or local trauma within a glandular tissue and is most commonly observed in the minor salivary glands of the oral mucosa. The importance of this condition arises from the fact that its clinical and histological aspects may raise issues of differential diagnosis with malignant neoplasms. The authors present a case of necrotizing sialometaplasia involving the lacrimal sac simulating a well-differentiated squamous cell carcinoma.
  
  
  METHODS
  A 52-year-old man presented with epiphora in the left eye after having sustained an orbital blowout fracture during a motor vehicle accident. During subsequent external dacryocystorhinostomy, an abnormal lacrimal sac mucosa was observed and analyzed histologically revealing a well-differentiated squamous cell carcinoma. However, the subsequent biopsies of the lacrimal sac were negative for malignancy; in view of these findings, two pathologists reviewed the first specimen and immunohistochemical staining was performed allowing us to arrive at a diagnosis of necrotizing sialometaplasia. We suggest the term necrotizing dacryocystometaplasia for the involvement at this site.
  
  
  CONCLUSIONS
  Although exceedingly unusual, necrotizing dacryocystomeplasia should be considered in patients presenting with epiphora in the appropriate clinical context. Notably, this condition can be mistaken for a malignant disease, presenting a diagnostic challenge both clinically and histopathologically.
authors.affiliation: a Oculoplastics, Consultants in Ophthalmic and Facial Plastic Surgery , Southfield , Michigan , USA.
authors.forename: Abraham
authors.initials: A
authors.lastname: Gomez
authors.affiliation: a Oculoplastics, Consultants in Ophthalmic and Facial Plastic Surgery , Southfield , Michigan , USA.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Gladstone
mesh_terms: D000063:Accidents, Traffic; D015415:Biomarkers / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005134:Eye Neoplasms / Q000175:diagnosis*; D005147:Facial Bones / Q000293:injuries; D006801:Humans; D007766:Lacrimal Apparatus Diseases / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009917:Orbital Fractures / Q000209:etiology / Q000601:surgery; D012797:Sialometaplasia, Necrotizing / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D015415:Biomarkers
keywords: Epiphora; nasolacrimal duct obstruction; necrotizing sialometaplasia; orbital trauma