Renal parenchymal malacoplakia.

Malacoplakia is a rare inflammatory disease which usually involves the bladder and only rarely affects the renal parenchyma. The clinical, radiographic, and pathological findings in 5 cases of renal parenchymal malacoplakia (RPM) are presented and 30 cases from the literature are reviewed. Most patients are middle-aged women with E. coli pyelonephritis. Radiographically, two patterns of involvement are recognized: multifocal and unifocal. The prognosis depends on the pattern and extent of RPM; long-term survival is possible with appropriate therapy.