Gallium-67-citrate scanning of renal parenchymal malacoplakia

The purpose of this article is to review the potential role of nuclear medicine scanning, especially with 67Ga, in the presumptive diagnosis and clinical management of patients with renal parenchymal malacoplakia (RPMP), a rare disease associated with coliform bacterial infection of the kidney and characterized by chronic unresolving inflammatory infiltrates containing von Hansemann macrophages in the renal parenchyma.

Published cases of RPMP were collected from the archival literature by searching the MEDLINE database and by reviewing bibliographic references contained in articles on malacoplakia. Data on the clinical features and radiographic evaluation of patients with RPMP were extracted from the clinical case reports.

Forty-three cases of RPMP published over the past 20 yr were identified. Ten of the 43 patients (23%) had 67Ga scanning as a component of their diagnostic evaluation. In all 10 patients, renal uptake of 67Ga was classified as intense. Two of those 10 patients had serial 67Ga scanning performed to assess response to antibiotic treatment; both patients exhibited decreased uptake or complete resolution of abnormal renal uptake over time, a finding also exhibited by our patient.

Intense renal uptake of 67Ga, typically in the clinical setting of fever, progressive renal failure and nephromegaly, strongly supports a diagnosis of RPMP. In those patients receiving prolonged antimicrobial therapy for RPMP, resolution of abnormal 67Ga uptake over time may provide an objective endpoint for treatment.