Replacement Lipomatosis of the Kidney

Abstract

eplacement renal sinus lipomatosis (RRSL) is an uncommon disorder characterized by renal sinus fat proliferation resulting from renal parenchymal atrophy, inflammation, or calculous disease. We present the sonographic features of RRSL secondary to nephrolithiasis in a 75-year-old man. The patient was successfully treated with lithotripsy. Several entities can resemble the appearance of RRSL, including malakoplakia, fat-containing tumors, and xanthogranulomatous pyelonephritis (XGP). Sonography and a high index of suspicion are helpful in making a diagnosis of RRSL.Received April 20, 2008, Case ReportThe patient was a 75-year-old man with a history of radical cystectomy for bladder carcinoma with a urostomy. He had intermittent urolithiasis, in which calculi were passed through his urostomy. The patient underwent sonography to assess for renal stones. Sonography revealed an enlarged left kidney marked by a proliferation of renal sinus fat visualized as homogeneously increased echogenicity and virtually replacing the entire renal parenchyma. Overall, the left kidney measured 13.1 cm. However, a small atrophic renal cortex was identified in the periphery. Moderate focal hydronephrosis was apparent distally, indicating a mass effect of sinus fat on the calyceal system. A large calculus was situated in the pelviureteral junction (Figure 1). Renal arterial flow was preserved. Sonographic findings of the right kidney were unremarkable except for a diffusely echogenic sinus, indicative of a fatty component compatible with age-related renal sinus lipomatosis (Figure 2).

Induction of resistance to murine tumor development is associated with alterations in the glycosylation of blood serum proteins

“…The occurrence of lipomatosis after cosmetic surgery also supports our view of complex balances (25)(26)(27)(28). Goshtasby et al (29) described a case of isolated symmetrical lipomatosis of soft tissue overlying the trochanters that developed a recurrence after liposuction treatment.…”

Idiopathic renal replacement lipomatosis: A diagnostic and therapeutic challenge

“…Although it is easy to diagnose a fatty mass on CT, to characterize this entity preoperatively as renal replacement lipomatosis is a clinical challenge. In almost all reported cases, the diagnosis was confirmed on histopathology only (1)(2)(3)(4)(5)(6). Hence, the best treatment in such cases is excision of fatty mass intotal.…”

“…The mass effect can cause vague pain and sometimes obstructive features when the mass causes obstruction at the level of the renal pelvis. They are usually identifiable by their specific imaging features unlike renal replacement lipomatosis, which has no specific features on imaging that can confirm diagnosis (6).…”

The Evaluation of Renal Replacement Lipomatosis with Computerized Tomography and Magnetic Resonance Imaging Findings: A Case Report

“…Calculi, renal atrophy, increased perirenal soft tissue, diffuse suppressed perirenal and sinus fat tissue and the non functional kidney with dilated ureter can be detected. In the differential diagnosis; angiomyolipoma, fat-containing tumors such as lipoma and liposarcoma, xanthogranulomatous pyelonephritis (XGP) and transitional cell carcinoma (TCC) are conceivable [1,3].…”

“…Although there can be a mass effect of the renal sinus lipomatous' on the collecting system it is not always symptomatic and generally detected bilaterally [1,2]. Renal replacement lipomatosis (RRL) is a milder version of renal sinus lipomatosis that generally detected unilaterally; associated with aging, renal atrophy, chronic urinary tract infections and more often related to the chronic calculous disease [1,3]. The cause is; advanced renal atrophy, destruction and fat tissue proliferation due to hydronephrosis and inflammation induced by chronic calculous disease.…”