title: Unique characteristics of malignant schneiderian papilloma.
abstract: OBJECTIVE
  To ascertain the characteristics unique to malignant schneiderian papilloma (MSP).
  
  
  METHODS
  A case-control study of all schneiderian papilloma (SP) patients treated between 1978 and 1997 was conducted. Comparison was made between patients with MSP and patients with benign SP (BSP).
  
  
  RESULTS
  A diagnosis of SP was made in 72 patients. Malignant changes, all of them the inverted papilloma subtype, were found in 8 of these patients. Three were diagnosed carcinoma in situ, and 5 were defined as invasive squamous cell carcinoma. At presentation, the MSP patients had significantly larger tumor spread into the ethmoid and sphenoid sinuses. The recurrence rate was significantly lower in SP patients treated with extensive surgical procedures. An association was found between the presence of malignant lesions and positive smoking history, subjective awareness of a nasal mass, and ethmoid and sphenoid sinus involvement. Also, histologic multicentricity was a feature more often seen in MSP than BSP and was a significant correlate with malignancy.
  
  
  CONCLUSIONS
  The physician evaluating a patient with SP should be aware of the features described and of their possible association with a malignant lesion.
authors.affiliation: Department of Otolaryngology, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Nachtigal
authors.forename: A
authors.initials: A
authors.lastname: Yoskovitch
authors.forename: S
authors.initials: S
authors.lastname: Frenkiel
authors.forename: I
authors.initials: I
authors.lastname: Braverman
authors.forename: L
authors.initials: L
authors.lastname: Rochon
mesh_terms: D000368:Aged; D002278:Carcinoma in Situ / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010212:Papilloma / Q000175:diagnosis / Q000473:pathology*