title: Anorectal amelanotic melanoma.
abstract: OBJECTIVE
  Anorectal melanoma is a rare, highly malignant tumour with a poor 5 year survival of 10%. Most anorectal melanomas have gross and/or histologic pigmentation, however about 30% of anorectal melanomas are amelanotic.
  
  
  METHODS
  We report three cases of amelanotic anorectal melanomas and integrate our data with six case reports of amelanotic malignant melanoma from the literature. Further we compare clinicopathological data and clinical outcome with large series of anorectal melanomas (both, amelanotic and pigmentated).
  
  
  RESULTS
  There were seven females and two males, of median age 62 years (range: 45-75 years). Rectal bleeding was the leading symptom in all cases with a mean duration of 4 months before diagnosis. Eight of nine patients developed distant metastases. Median survival was 14 months (range: 3-60 months). A tumour thickness of < 4 mm was correlated with long-term disease-free survival, whereas tumour thickness of 4 mm or more was correlated with systemic recurrence.
  
  
  CONCLUSIONS
  Early diagnosis is key for efficient treatment and improved survival rate for patients with this unusual variant of melanoma. There is no difference in terms of age, time of diagnosis, stage and survival between pigmented and amelanotic anorectal melanoma.
authors.affiliation: Department of General, Visceral, and Transplantation Surgery, University of Ulm, Ulm, Germany. andreas.hillenbrand@uniklinik-ulm.de
authors.forename: A
authors.initials: A
authors.lastname: Hillenbrand
authors.forename: T F E
authors.initials: TF
authors.lastname: Barth
authors.forename: D
authors.initials: D
authors.lastname: Henne-Bruns
authors.forename: A
authors.initials: A
authors.lastname: Formentini
mesh_terms: D000368:Aged; D001005:Anus Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D018328:Melanoma, Amelanotic / Q000175:diagnosis / Q000401:mortality / Q000473:pathology; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology; D015996:Survival Rate