title: Morphology of pilonidal sinus disease: some evidence of its being a unilocalized type of hidradenitis suppurativa.
abstract: BACKGROUND
  The term 'pilonidal sinus' (PS) reflects an acute exacerbating, purulent, fistulating chronic inflammation located in the coccyx region. Systematic histological investigations are scarce, and the etiology has remained controversial.
  
  
  METHODS
  Histological and immunohistochemical characterization of totally excised material of 27 patients (68 specimens) with PS (no antecedent and no current clinical signs of hidradenitis suppurativa, HS) and its correlation with data on HS which we published earlier.
  
  
  RESULTS
  Follicular hyperplasia/hyperkeratosis and interfollicular epidermal hyperplasia are main features of PS. Early pathology seems to take place at terminal hair follicles, whereas sinus tract formations are a secondary event. Focused regions show an inflammatory mixed infiltrate consisting of CD3+, CD4+, CD8+, CD68+ and CD79+ cells.
  
  
  CONCLUSIONS
  PS and HS have various common characteristics at the histological and immunohistochemical level. Considering PS as a unilocalized type of HS, risk factors known in the latter should henceforth be evaluated in PS as well.
authors.affiliation: Department of Dermatology and Venereology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany. maximilian.von-laffert @charite.de
authors.forename: Maximilian
authors.initials: M
authors.lastname: von Laffert
authors.forename: Volker
authors.initials: V
authors.lastname: Stadie
authors.forename: Jens
authors.initials: J
authors.lastname: Ulrich
authors.forename: Wolfgang Christian
authors.initials: WC
authors.lastname: Marsch
authors.forename: Johannes
authors.initials: J
authors.lastname: Wohlrab
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000276:immunology; D005260:Female; D018859:Hair Follicle / Q000276:immunology / Q000473:pathology; D017497:Hidradenitis Suppurativa / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D008297:Male; D010864:Pilonidal Sinus / Q000276:immunology / Q000473:pathology*; D055815:Young Adult
chemical_list: D015703:Antigens, CD