Bilateral renal loss resulting from intravesical formalin instillation

A patient was referred for evaluation of obstructive uropathy after treatment with 10% formalin to control recurrent hemorrhagic radiation cystitis. Progressive bilateral ureteral, pelvic, and renal parenchymal destruction occurred despite ileal ureteral replacement. This complication of therapy reinforces the concept that vesical instillation of formalin should be done only in extreme cases and then only in low concentrations.