Case report: acute focal bacterial pyelonephritis (lobar nephronia)--presentation as a palpable abdominal mass.

Acute lobar nephronia, or focal pyelonephritis, is an uncommon form of renal infection with a distinct computerized tomographic appearance. A patient is presented with lobar nephronia characterized by fever, flank pain, urosepsis, and painful abdominal mass. Differentiating this condition from abscess or other renal mass is important, because the treatment of lobar nephronia is nonsurgical. The infection responds to antibiotic therapy.