Renal Sinus Lipomatosis
A condition of benign proliferation of adipose tissue within renal sinus, hilum, and perirenal space, replacing the renal parenchyma. Renal replacement lipomatosis is characterized by complete replacement of the kidney by adipose tissue, with varying degrees of fibrosis (Ratkal et al. 2015).
Both male and female.
Renal sinus, hilum, and perirenal space.
The kidney is usually enlarged and presents with a gross fibro-fatty appearance and renal cortical atrophy. It is usually associated with chronic pyelonephritis, renal lithiasis, and hydronephrosis. The shape of the kidney is always preserved (Rha et al. 2004).
Differential diagnoses include: xanthogranulomatous pyelonephritis, angiomyolipoma, lipomas, and liposarcomas. Xanthogranulomatous pyelonephritis (XGP) is the major differential diagnosis in the presence of longstanding inflammation and calculus obstruction. XGP is a chronic infection characterized by destruction of the renal tissue. Histologically, the characteristic of XGP is an increase of lipid-laden macrophages (xanthoma cells) in the renal parenchyma, whereas replacement lipomatosis contains large fat cells outside of the renal parenchyma.
Angiomyolipoma is composed by a mixture of adipose tissue, vessels, and spindle cells. Whenever in doubt, specific immunohistochemistry is applied (Ratkal et al. 2015).
References and Further Reading
- Ratkal, V., Chawla, A., Mishra, D. K., & Krishna, S. (2015). Renal replacement lipomatosis of the right kidney. BML Case Reports, 6, 2015.Google Scholar