Bladder calcifications after photodynamic therapy: analysis of a rare complication.
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.
Walther
M M
MM
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20898, USA.
Eanes
E D
ED
Delaney
T F
TF
Travis
W D
WD
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