title: Urinary bladder melanosis associated with urothelial dysplasia and invasive urothelial carcinoma: a report of two cases.
abstract: BACKGROUND
  Melanosis is defined as an abnormal or excessive deposition of melanin within cells and/or tissues. It typically presents as a cutaneous or buccal mucosal lesion, but rare cases of bladder melanosis have also been documented. Melanosis of the urinary bladder is typically considered a benign condition, but it has also been described in association with malignant melanoma and urothelial carcinoma.
  
  
  METHODS
  We report the cases of 2 patients who presented with melanosis of the urinary bladder. One patient presented with melanosis of the urinary bladder together with urothelial dysplasia. Melanosis was incidentally identified during a cystoscopy for ureteral stones. A second patient presented with hematuria and was found to have a muscle invasive urothelial carcinoma with focal small nested morphology together with melanosis. We also present a literature review of the bladder melanosis and an overview of other bladder melanocytic lesions, which include primary and metastatic melanoma and blue nevus.
  
  
  CONCLUSIONS
  Initial evaluation for bladder melanosis should include cystoscopy and upper urinary tract imaging. Biopsy is essential to establish the diagnosis and rule out associated malignancy.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, Alberta, Canada.
authors.forename: Premal
authors.initials: P
authors.lastname: Patel
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Gotto
authors.forename: Alex
authors.initials: A
authors.lastname: Kavanagh
authors.forename: Samir
authors.initials: S
authors.lastname: Al Bashir
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Bismar
authors.forename: Kiril
authors.initials: K
authors.lastname: Trpkov
mesh_terms: D000368:Aged; D002295:Carcinoma, Transitional Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008548:Melanosis / Q000473:pathology*; D008875:Middle Aged; D001745:Urinary Bladder Diseases / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*; D019459:Urothelium / Q000473:pathology*