title: Basaloid squamous cell carcinoma of the nasal septum presenting as a primary cutaneous lesion.
abstract: BACKGROUND
  Basaloid squamous cell carcinoma is a rare aggressive variant of squamous cell carcinoma, with a predilection for the head and neck region. There are only two case reports in the literature documenting a nasal cavity squamous cell carcinoma presenting as a primary cutaneous lesion.
  
  
  OBJECTIVE
  We report a rare case of nasal cavity basaloid squamous cell carcinoma presenting initially as a nasal bridge mass. Two initial biopsies revealed features consistent with basal cell carcinoma and basosquamous cell carcinoma, respectively.
  
  
  RESULTS
  Final surgical pathology showed extensive invasive squamous cell carcinoma with basaloid differentiation arising from the nasal septal mucosa with extension to the overlying skin. The clinicopathologic features were interpreted as basaloid squamous cell carcinoma.
  
  
  CONCLUSIONS
  We discuss the difficulties in pathologic diagnosis of this condition given its varied phenotypical expression. As well, this case emphasizes the necessity for diagnostic vigilance when assessing a primary cutaneous lesion as it may be a rare presentation of an underlying malignancy extending to the skin.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada. nhoy@ualberta.ca
authors.forename: Nathan
authors.initials: N
authors.lastname: Hoy
authors.forename: Joyce
authors.initials: J
authors.lastname: Wong
authors.forename: Muhammad
authors.initials: M
authors.lastname: Mahmood
authors.forename: Alain
authors.initials: A
authors.lastname: Brassard
mesh_terms: D001706:Biopsy; D002281:Carcinoma, Basosquamous / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009300:Nasal Septum; D009669:Nose Neoplasms / Q000473:pathology*