title: Melanonychia following mohs surgery for recurrent squamous cell carcinoma in situ of the nail bed.
abstract: BACKGROUND
  Longitudinal melanonychia (LM) is characterized by the appearance of a longitudinal pigmented band in the nail plate. Melanonychia can occur from many causes, including racial predisposition, trauma, drugs, pregnancy, Addison disease, Peutz-Jeghers syndrome, Laugier-Hunziker syndrome, Bowen disease, onychomycosis, benign nail matrix nevi, and melanoma.
  
  
  OBJECTIVE
  We present a case of diffuse melanonychia developing several months following Mohs surgery for a human papillomavirus-induced recurrent squamous cell carcinoma in situ of the nail bed.
  
  
  CONCLUSIONS
  This case illustrates the diagnostic dilemma in determining the etiology of the melanonychia and considers the differential diagnosis.
authors.affiliation: Dermatology Service and Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Jules B
authors.initials: JB
authors.lastname: Lipoff
authors.forename: Alon
authors.initials: A
authors.lastname: Scope
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Busam
authors.forename: Kishwer S
authors.initials: KS
authors.lastname: Nehal
mesh_terms: D000328:Adult; D001706:Biopsy; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008548:Melanosis / Q000473:pathology* / Q000601:surgery*; D015580:Mohs Surgery; D009260:Nail Diseases / Q000473:pathology / Q000601:surgery*; D009364:Neoplasm Recurrence, Local