title: Bladder calcifications after photodynamic therapy: analysis of a rare complication.
abstract: OBJECTIVE
  We analyzed bladder calcifications occurring after photodynamic therapy administered for the treatment of superficial bladder cancer, a finding not previously reported after this treatment.
  
  
  METHODS
  Bladder biopsies from 20 patients undergoing photodynamic therapy were evaluated. Bladder calcifications were identified in 2 patients and analyzed for composition.
  
  
  RESULTS
  One patient had diffuse microcrystalline deposition in two biopsies composed of calcium oxalate monohydrate A. A second patient had a focal stone at a healing biopsy site composed of monoclinic calcium hydrogen phosphate dihydrate (brushite) (66%), calcium oxalate (25%), hydroxyapatite (6%), and protein (3%).
  
  
  CONCLUSIONS
  Rare calcium oxalate and brushite calcifications were identified after photodynamic therapy and presumed to occur because of tissue injury associated with treatment.
authors.affiliation: Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20898, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Walther
authors.forename: E D
authors.initials: ED
authors.lastname: Eanes
authors.forename: T F
authors.initials: TF
authors.lastname: Delaney
authors.forename: W D
authors.initials: WD
authors.lastname: Travis
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000209:etiology*; D002278:Carcinoma in Situ / Q000188:drug therapy; D003460:Crystallization; D006801:Humans; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy / Q000009:adverse effects*; D001745:Urinary Bladder Diseases / Q000209:etiology*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy