title: Johnson square procedure for lentigo maligna and lentigo maligna melanoma.
abstract: BACKGROUND
  Lentigo maligna (LM) and lentigo maligna melanoma (LMM) can be difficult to manage surgically. Predetermined margins can be inadequate because of subclinical spread, or can affect function when margins are adjacent to the eye or mouth.
  
  
  OBJECTIVE
  To describe our 5-year experience in Nottingham of using the staged square procedure (Johnson square) in excising difficult facial LM and LMM.
  
  
  METHODS
  The square procedure is a staged technique useful for ill-defined lesions and for lesions that have a high recurrence rate due to subclinical spread. It uses paraffin wax-embedded peripheral vertical sections for margin control, ensuring complete clearance as the surgical margins are usually examined at distances of 2-5 mm from the periphery of the lesion.
  
  
  RESULTS
  We treated 21 patients with LM or LMM with the staged square procedure over a 5-year period. Of the 21 patients, 10 needed only one stage of surgery, 6 needed two stages, 3 needed three stages and 2 needed four stages. To date, there has been only one recurrence, which was of an extensive lesion that crossed the medial canthus, making margin control impossible because of the anatomical limitations.
  
  
  CONCLUSIONS
  The staged square procedure is an effective treatment for LM and LMM. It attempts to conserve tissue while ensuring a higher clearance rate. This offers favourable cosmetic outcomes and better prognosis, especially for facial LM and LMM.
authors.affiliation: Department of Dermatology, Queen's Medical Centre, Nottingham, UK.
authors.forename: A N
authors.initials: AN
authors.lastname: Patel
authors.forename: W
authors.initials: W
authors.lastname: Perkins
authors.forename: I H
authors.initials: IH
authors.lastname: Leach
authors.forename: S
authors.initials: S
authors.lastname: Varma
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005153:Facial Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015580:Mohs Surgery / Q000379:methods*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology / Q000601:surgery*