title: Invasive Squamous Cell Carcinoma: A Comparison of Tumors With or Without Horn Presentation Based on Age, Sex, Anatomic Site, Tumor Diameter, Depth of Invasion, and Grade of Differentiation in 1,666 Cases.
abstract: BACKGROUND
  Invasive squamous cell carcinoma (SCC) may present clinically with or without a horn.
  
  
  OBJECTIVE
  To compare invasive SCC with or without horn presentation by anatomic site, tumor diameter, depth, and grade of differentiation.
  
  
  METHODS
  The above characteristics of invasive SCC with or without horns were compared using a logistic regression model adjusted for potential confounders.
  
  
  RESULTS
  There were 7.0% horns (n = 116) and 93.0% nonhorns (n = 1,550) in 1,666 cases. The median tumor diameter was 6 mm for horns, and 8 mm for nonhorn cases, p < .001. The median depth of invasion was 0.8 mm for horn cases and 1.3 mm for nonhorns, p < .001. Most cases were well-differentiated SCC for both horns (n = 102, 87.9%) and nonhorns (n = 1,265, 81.6%) p = .07. Horn cases had a borderline significant shift to well differentiation with moderate differentiation in 11.2% of cases (n = 13) and poor differentiation in 0.9% (n = 1).
  
  
  CONCLUSIONS
  Horns presented on invasive SCC with reduced tumor diameters and reduced invasion depths compared to nonhorns. Horns presenting on invasive SCC were usually well differentiated. However, moderate and even poor differentiation can occur within a horn base.
authors.affiliation: *School of Medicine, The University of Queensland, Brisbane, Australia; †School of Public Health, The University of New South Wales, Sydney, Australia.
authors.forename: John H
authors.initials: JH
authors.lastname: Pyne
authors.forename: Esther
authors.initials: E
authors.lastname: Myint
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barr
authors.forename: Simon P
authors.initials: SP
authors.lastname: Clark
authors.forename: Renhua
authors.initials: R
authors.lastname: Na
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001415:Back; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000473:pathology*; D005153:Facial Neoplasms / Q000473:pathology*; D005260:Female; D005542:Forearm; D006225:Hand; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D012189:Retrospective Studies; D012737:Sex Factors; D012871:Skin Diseases / Q000150:complications / Q000473:pathology; D012878:Skin Neoplasms / Q000150:complications / Q000473:pathology*; D047368:Tumor Burden