title: Hidradenitis suppurativa: MRI features in anogenital disease.
abstract: BACKGROUND
  Hidradenitis suppurativa is a rare chronic inflammatory disorder of apocrine gland-bearing skin, which commonly affects the anogenital region. There has been very little literature to date on the MRI appearances of anogenital hidradenitis suppurativa.
  
  
  OBJECTIVE
  The aim of this study was to assess the MRI features of anogenital hidradenitis suppurativa in the largest cohort of patients to be published to date.
  
  
  METHODS
  After an institutional review board waiver, patients with hidradenitis suppurativa who were undergoing MRI for anogenital disease between 2005 and 2012 were identified from our institutional database. The MRI appearances were recorded by 2 radiologists in consensus, blinded to clinical details. Location of disease, number of tracts, presence of anal fistula, and supralevator involvement were recorded. Patient demographics were also noted.
  
  
  METHODS
  This study was conducted at the Department of Radiology, Guy's and St Thomas' National Health Service Foundation Trust.
  
  
  METHODS
  Patients included were those undergoing MRI for anogenital disease in hidradenitis suppurativa between 2005 and 2012.
  
  
  METHODS
  The distribution of sinus tracts in anogenital hidradenitis suppurativa on MRI was measured.
  
  
  RESULTS
  Thirty-one MRIs were performed in 18 patients (15 men; mean age, 46 years). On the baseline MRI, multiple tracts were seen in the natal cleft (16/18; 83%), the perianal (12/18; 61%), the perineal (13/18; 56%), and the gluteal (8/18; 44%) regions. A communication with the anal canal was present in only 4 patients. Three patients had supralevator extension. Seven patients had follow-up MRIs with variable response to interval treatment: 3 of 7 showed responding disease, 3 of 7 showed stable disease, and 1 of 7 showed progressive disease.
  
  
  CONCLUSIONS
  This study was limited by its relatively small cohort of patients.
  
  
  CONCLUSIONS
  In hidradenitis suppurativa, anogenital disease is usually subcutaneous but extensive, with only a minority of patients demonstrating deeper involvement. MRI may help define the extent of anogenital disease and assess response to treatment.
authors.affiliation: 1Department of Radiology, Guy's and St Thomas' National Health Service Foundation Trust, London, United Kingdom 2Department of General Surgery, Guy's and St Thomas' National Health Service Foundation Trust, London, United Kingdom 3Department of Gastroenterology, Guy's and St Thomas' National Health Service Foundation Trust, London, United Kingdom 4Department of Dermatology, Guy's and St Thomas' National Health Service Foundation Trust, London, United Kingdom 5Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom.
authors.forename: Nyree
authors.initials: N
authors.lastname: Griffin
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Williams
authors.forename: Simon
authors.initials: S
authors.lastname: Anderson
authors.forename: Peter M
authors.initials: PM
authors.lastname: Irving
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sanderson
authors.forename: Nemesha
authors.initials: N
authors.lastname: Desai
authors.forename: Vicky
authors.initials: V
authors.lastname: Goh
mesh_terms: D000328:Adult; D000368:Aged; D001003:Anal Canal; D002081:Buttocks; D005260:Female; D006119:Groin; D017497:Hidradenitis Suppurativa / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010502:Perineum; D012189:Retrospective Studies; D055815:Young Adult