title: Squamous cell carcinoma development in previously diagnosed oral lichen planus: de novo or transformation?
abstract: OBJECTIVE
  The objectives of this study were to investigate the incidence of oral squamous cell carcinoma (OSCC) developing in lesions that were previously diagnosed as oral lichen planus (OLP), and to evaluate potential contributing factors that might be associated with an increased risk for the development of OSCC in these patients.
  
  
  METHODS
  We retrospectively reviewed a relatively large cohort of 518 patients with OLP who received long-term follow-up (range, 6 months-21.5 years).
  
  
  RESULTS
  There were 353 females and 165 males. Of these, 5 (0.96%) patients developed OSCC with a mean duration of 70 months. All were females with no history of smoking or alcohol use. Four of them received corticosteroid therapy. Notably, 1 of these patients received systemic corticosteroid therapy 13 months before transformation, and died of metastatic disease 46 months after transformation.
  
  
  CONCLUSIONS
  The incidence of OSCC developing in lesions previously diagnosed as OLP is less than 1%, and females were more commonly affected. These cases appear to represent the transformation of OLP into OSCC, however it cannot be entirely ruled out that these cases may represent de novo OSCC.
authors.affiliation: Department of Dermatology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Shen
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Jin-Qiu
authors.initials: JQ
authors.lastname: Feng
authors.forename: Hai-Wen
authors.initials: HW
authors.lastname: Zhou
authors.forename: Zeng-Tong
authors.initials: ZT
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017676:Lichen Planus, Oral / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology*; D011230:Precancerous Conditions / Q000473:pathology*; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult