[Eosinophilic cystitis. Apropos of a case]

We report a case of eosinophilic cystitis (EC) in an elderly patient who had previously undergone transurethral resection of a bladder tumor which is the reason why this diagnosis was not taken into consideration and was discovered by the pathologist in a fragment whose intraoperative diagnosis had been that of tumor recurrence. We describe the radiologic features of this disease entity and its similarity to other malignant conditions. Because of the foregoing, a differential diagnosis--both clinical as well as radiologic--must be made.