Ureteral involvement complicating eosinophilic cystitis

A thirty-three-year-old woman was evaluated for eosinophilia, irritative bladder symptoms, and renal insufficiency. Eosinophilic cystitis was documented by bladder biopsy and glomerulonephritis by renal biopsy. As the glomerulonephritis and other symptoms resolved, unilateral ureteral obstruction developed with irreversible loss of right renal function. The distal ureter was found to have eosinophilic infiltration. This entity should be considered in the differential diagnosis of unilateral ureteral obstruction associated with cystitis.