[Acute focal bacterial nephritis. Pathology mimicking renal masses].

Focal acute bacterial nephritis is an uncommon form of renal acute infection with a clinical presentation that, although similar to other acute infections of the renal parenchyma, must be taken into account in order to reach a correct differential diagnosis with other processes which have very similar radiological images but highly different management approaches, such as the renal carcinoma. This paper present one case in which the sings and symptoms were crucial to establish the diagnosis.