title: A prospective evaluation of the clinical, histologic, and therapeutic variables associated with incidental perineural invasion in cutaneous squamous cell carcinoma.
abstract: BACKGROUND
  The prognosis and management of incidental perineural invasion (PNI) in patients with cutaneous squamous cell carcinoma (CSCC) has not been well defined.
  
  
  OBJECTIVE
  We sought to investigate the clinical, histologic, and treatment characteristics associated with incidental PNI, histologic PNI extending beyond the tumor bulk, in patients with CSCC.
  
  
  METHODS
  We conducted a multicenter prospective analysis of patients with CSCC undergoing Mohs micrographic surgery.
  
  
  RESULTS
  The incidence of PNI was 4.6% in 753 CSCC cases. PNI was significantly associated with tumors of the head and neck (P = .039), larger tumor diameter (P < .001), presence of clinically palpable lymphadenopathy (P = .012), and recurrent (P < .001) and painful (P < .001) tumors. Further, PNI was significantly associated with poor tumor differentiation (P < .001), greater tumor thickness (P < .001), a greater number of Mohs stages (P < .001), and larger estimated maximum Mohs margin (P < .001) required to clear the tumor.
  
  
  CONCLUSIONS
  The low numbers of patients demonstrating incidental PNI limits this study.
  
  
  CONCLUSIONS
  The association of incidental PNI with clinicopathological indicators of poor prognosis suggests that incidental PNI may serve as a marker to improve the precision in the prognostic assessment of patients with CSCC.
authors.affiliation: Fairview Medical Group, Minneapolis, Minnesota. Electronic address: mcampol1@fairview.org.
authors.forename: Michael
authors.initials: M
authors.lastname: Campoli
authors.affiliation: Zitelli and Brodland PC, Pittsburgh, Pennsylvania.
authors.forename: David G
authors.initials: DG
authors.lastname: Brodland
authors.affiliation: Zitelli and Brodland PC, Pittsburgh, Pennsylvania.
authors.forename: John
authors.initials: J
authors.lastname: Zitelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D002294:Carcinoma, Squamous Cell / Q000556:secondary / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D015580:Mohs Surgery / Q000379:methods; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D010524:Peripheral Nervous System Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D011446:Prospective Studies; D018570:Risk Assessment; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome
keywords: Mohs micrographic surgery; perineural invasion; prognostic factors; squamous cell carcinoma