Renal Replacement Lipomatosis—A Rare Benign Condition

Abstract

Introduction: Renal replacement lipomatosis is a rare condition that occurs at the end of the spectrum of renal tissue replacement by fat. It is usually unilateral and occurs as a result of severe renal atrophy or destruction usually due to chronic calculus disease, chronic pyelonephritis and renal tuberculosis. The most commonly used diagnostic investigation remains CECT (contrast enhanced computed tomography) scan. Herein we report our series of patients with total renal replacement lipomatosistreated by nephrectomy. Materials & Methods: We retrospectively reviewed our hospital data for cases of RRL, presented and treated during the period Jan. 2006-Dec. 2015. The age, gender, presenting symptoms, clinical and laboratory findings were noted. The indications for surgery, postoperative outcomes and complications were similarly noted and analyzed. Results: Five patients (three females and two males) with a mean age of 48.4 ± 3.2 years presented with symptoms of pain. Computed tomography (CT) in these patients showed the affected kidney to be completely distorted and replaced by ill-defined fatty attenuating lesion. Open nephrectomy was done in all these patients. Histo-pathological report (HPR) revealed features of RRL with renal calculi. Conclusions: Renal replacement lipomatosis is an uncommon entity, and one should have a high index of suspicion when dealing with suspicious lesions similar to xanthogranulomatous pyelonephritis. Specific imaging, operative, and pathological differences may provide clues for the differential diagnosis.

Malakoplakia and xanthogranulomatous pyelonephritis treated with nephrectomy

“…[ 17 ] Other possible factors include abnormal lipid metabolism, lymphatic blockage, venous occlusion, hemorrhage, urinary tract infection, altered immunologic competence, and renal ischemia. [ 18 ] The primary obstacle to the correct treatment of XGP is incorrect diagnosis. [ 19 ] XGP is usually found in patients with urinary tract infection and a unilateral, enlarged, non-functioning or poorly functioning kidney with urolithiasis.…”

“…Infection in a primarily obstructed kidney may lead to tissue destruction and the collection of lipid-laden macrophages [17] . Other possible factors include abnormal lipid metabolism, lymphatic blockage, venous occlusion, hemorrhage, urinary tract infection, altered immunologic competence, and renal ischemia [18] . The primary obstacle to the correct treatment of XGP is incorrect diagnosis [19] .…”