Renal replacement lipomatosis: ultrasonography and computed tomography findings

Abstract

Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. The diagnosis is difficult to establish with conventional radiographic methods. Although ultrasonography may show highly suggestive findings, computed tomography seems to be the most accurate method for demonstrating the distinctive features of replacement lipomatosis. Ultrasonographic and computed tomographic features in three cases of replacement lipomatosis of the kidney are reported.

Renal Replacement Lipomatosis with Psoas Abscess Mimicking as Xanthogranulomatous Pyelonephritis

“…Renal replacement lipomatosis (RRL) also known as fibrolipomatosis is an uncommon condition, which occurs secondary to atrophy or destruction of renal parenchyma by chronic inflammation. RRL is most commonly seen in association with calculus disease (in >70% patients), however it can be associated with other chronic inflammatory pathologies such as chronic pyelonephritis, renal tuberculosis and transplant patients [1,2].…”

“…Fat proliferation begins from the renal sinus also called as renal sinus lipomatosis and eventually replaces the entire renal and perirenal tissue by lipomatous mass in more severe form called as total replacement lipomatosis [1]. The disease process is presumed to contribute to atrophy of renal parenchyma by increasing pressure over pelvi-calyceal system or direct parenchymal invasion which helps to distinguish this from other medical conditions causing increase in retroperitoneal fat volume like obesity, Cushing's disease or long-term exogenous steroid exposure [3].…”

Renal replacement lipomatosis: A rare type of renal pseudotumor

“…It is associated with long-standing inflammation and calculi in 76%-79% of cases. [13] The occurrence of RRL in native kidneys following renal transplantation suggests the involvement of other mechanisms as well. [4]…”

“…It is seen with calculus disease in 70% of cases and associated with chronic inflammation and hydronephrosis. [1] This entity may mimic and can be confused with a fatty neoplasm of kidney. We report CT features of a case of RRL and coexistent xanthogranulomatous pyelonephritis in an elderly male, with emphasis on the differential considerations.…”

Renal Replacement Lipomatosis—A Rare Benign Condition

“…RRL, renal sinus lipomatosis and fibro-lipomatosis represent the various stages of the same disease, wherein the normal renal sinus fat and the peri-renal fat gradually increase to replace the renal parenchyma. Renal sinus lipomatosis which is the mildest form, is usually associated with obesity, renal atrophy (secondary to aging, atherosclerosis), Cushing's syndrome or the use of exogenous steroids [2] [4] [5]. This mild form rarely produces symptoms because of the absence of calyceal obstruction [4], and is a common finding at autopsy [2].…”