Objective: We present the case of a patient with eosinophilic ureteritis.
Methods: The patient was admitted with pain on the right renal fossa, and after several imaging tests, a mass was found on the right ureter, compatible with urothelial neoplasia on the right ureter.
Results: Right nephroureterectomy was performed and the histopathological diagnosis was eosinophilic ureteritis
Conclusion: Eosinophilic ureteritis is a rare entity with an unclear etiology,which is not easily distinguished from urothelial tumours. In the differential diagnosis we must take it into account whenever we find a ureteral mass associated to eosinophilia.