CASE 11934 Published on 30.06.2014

Renal replacement lipomatosis in transplant kidney


Uroradiology & genital male imaging

Case Type

Clinical Cases


Chirag Kanjibhai Ghodasara, R.Ganesh, N.Karunakaran, T.Mukuntharajan

Department of Radiology, Meenaxi Mission Hospital and Research Centre, Mellur road, Madurai, Tamilnadu, India;

58 years, male

Area of Interest Kidney ; Imaging Technique CT
Clinical History
A 58 year old male patient with transplant kidney was presented with decreased urine output, left sided chronic loin pain and features of transplant failure.
Imaging Findings
Abdominal non-contrast CT revealed contracted bilateral native kidneys. A transplant kidney was noted in the left iliac fossa with atrophy of its renal parenchyma. Fat proliferation was noted in the renal sinus, hilum and perirenal space of the transplant kidney. Small ureteric calculus was noted in the transplant ureter causing obstructive uropathy.
Renal replacement lipomatosis is a chronic condition characterised by fat proliferation in the renal sinus, renal hilum and perirenal space. It occurs due to destruction and atrophy of renal parenchyma because of long standing inflammation mostly due to calculus disease. Other causes are aging, renal tuberculosis, steroids and post renal transplant [1].
Renal sinus lipomatosis is a benign condition in which the perirenal fat proliferates to a variable degree around the kidney, the ureter, and the intrarenal collecting system, but does not cause renal impairment. If it is associated with atrophy of renal tissue, it is defined as renal replacement lipomatosis [2].
The patient with renal replacement lipomatosis in a transplant kidney is presented with acute renal failure mostly due to calculus disease or compression of renal parenchyma by fat. Steroid therapy in the transplant patient is causes a paradoxical effect by fat proliferation [2].
Ultrasound, CT or MRI is required for diagnosis. On ultrasound, there is an echogenic lesion in the renal sinus, renal hilum and perirenal area with atrophy of renal parenchyma. On CT, fatty replacement of renal parenchyma and calculus can be seen [1]. Renal biopsy is confirmatory for this disease.
Renal replacement lipomatosis is an uncommon entity, and a high index of suspicion
is necessary to achieve an accurate diagnosis [1]. Renal replacement lipomatosis in a transplant kidney occurs at the end stage of the disease and ultimately causes transplant failure [2].
The main differential considerations for renal replacement lipomatosis include malakoplakia, fat containing tumours such as liposarcomas, lipomas, and angiomyolipomas, xanthogranulomatous pyelonephritis and transitional carcinoma of the renal sinus [3].
Renal liposarcoma is located peripherally (between the kidney and renal capsule), and does not produce a defect in renal parenchyma. Again, in cases of angiomyolipoma/lipoma, atrophy of renal parenchyma, calculi and absence of renal contrast concentration and excretion are not observed [3].
Differential Diagnosis List
Renal replacement lipomatosis in transplant kidney
Renal lipoma
Renal liposarcoma
Renal angiomyolipoma
Final Diagnosis
Renal replacement lipomatosis in transplant kidney
Case information
DOI: 10.1594/EURORAD/CASE.11934
ISSN: 1563-4086