Renal replacement lipomatosis

Renal replacement lipomatosis is a rare condition characterized by fatty tissue proliferation in the renal sinus and perinephric space with marked destruction/atrophy of renal parenchyma (due to chronic inflammation).

Patients usually present with non-specific complaints like flank pain, fever and weight loss. Sometimes a patient may directly complain of a vague flank mass.

It has been associated with aging, calculus disease (nearly 70% of cases), renal tuberculosis and post-transplantation. It may also be associated with fibrotic changes to a varying degree.

An advanced stage of xanthogranulomatous pyelonephritis is another common association.

It is considered to be on the extreme end of a spectrum with renal sinus lipomatosis being the mildest form. The condition is usually unilateral.

Usually shows calculi and displacement of the bowel.

It is usually difficult to come to a diagnosis on ultrasound alone but it may show an echogenic mass suggestive of fatty tissue and calculi in the atrophic renal tissue.

It is diagnostic and shows typical features including:

  • renal parenchymal atrophy/destruction
  • perinephric and hilar lipomatosis
  • renal calculi
  • perinephric abscesses which may extend to the psoas muscle

Possible differential considerations include:

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Article information

rID: 45372
System: Urogenital
Tag: cases, renal
Synonyms or Alternate Spellings:
  • Replacement lipomatosis of the kidney
  • Renal fibrolipomatosis

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