title: Skin appendage involvement in anal intraepithelial neoplasia.
abstract: BACKGROUND
  High-grade anal intraepithelial neoplasia (AIN III) may be premalignant. Surgical excision of large areas of anal epithelium carries significant morbidity. Ablation treatments may carry less morbidity; however, the depth of ablation is uncertain and failure to ablate dysplasia in hair shafts and other skin appendages may lead to early recurrence.
  
  
  METHODS
  This study assesses morphometric aspects of skin appendages in perianal skin and anal canal mucosa in tissues from 30 patients with AIN III. Both normal and dysplastic epithelium was assessed in each patient. The depth to which AIN III involved skin appendages was measured using computerized image analysis.
  
  
  RESULTS
  Both the perianal epidermis and anal canal mucosa affected by AIN III were significantly thicker than normal. Nineteen of 30 patients with AIN III had skin appendage involvement. Some 57 per cent of hair follicles (79 of 138), 16 per cent of sebaceous glands (11 of 69) and 25 per cent of sweat glands (24 of 96) observed beneath an abnormal epithelium had evidence of AIN. The median depth of AIN involvement of the hair follicle was 1.14 (range 0.44-1.67) mm, sebaceous glands 1.44 (range 0.96-1.90) mm, and sweat glands 0.94 (range 0.50-2.20) mm. These figures do not take into account tissue shrinkage due to histological processing.
  
  
  CONCLUSIONS
  AIN III involvement of epithelial appendages is a significant problem. For disease eradication, tissue destruction or removal to a depth of at least 2.2 mm below the adjacent basement membrane is required. Surgical excision of high-grade AIN remains the treatment of choice.
authors.affiliation: Department of Surgery, Northern General Hospital, Sheffield, UK.
authors.forename: P P
authors.initials: PP
authors.lastname: Skinner
authors.forename: O A
authors.initials: OA
authors.lastname: Ogunbiyi
authors.forename: J H
authors.initials: JH
authors.lastname: Scholefield
authors.forename: R D
authors.initials: RD
authors.lastname: Start
authors.forename: J H
authors.initials: JH
authors.lastname: Smith
authors.forename: F
authors.initials: F
authors.lastname: Sharp
authors.forename: K
authors.initials: K
authors.lastname: Rogers
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000473:pathology*; D001706:Biopsy; D002278:Carcinoma in Situ / Q000473:pathology; D006201:Hair Diseases / Q000473:pathology; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology; D008875:Middle Aged; D011230:Precancerous Conditions / Q000473:pathology*; D012626:Sebaceous Gland Neoplasms / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology*