Encyclopedia of Pathology

Living Edition
| Editors: J.H.J.M. van Krieken

Renal Sinus Lipomatosis

  • Alessia Cimadamore
  • Rodolfo MontironiEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-28845-1_4927-1

Synonyms

Definition

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).

Clinical Features

  • Incidence

    Rare.

  • Age

    Any age.

  • Sex

    Both male and female.

  • Site

    Renal sinus, hilum, and perirenal space.

  • Treatment

    None.

  • Outcome

    Benign.

Macroscopy

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).

Microscopy

The renal cortex is extremely atrophied, with varying degrees of hydronephrosis or pyonephrosis as well as acute and chronic pyelonephritic changes. There is marked proliferation of adipose tissue in the renal sinus, with extremely large adipocytes that do not infiltrate the renal parenchyma but merely develop adjacent to it, as it atrophies. (Ratkal et al. 2015) (Fig. 1).
Fig. 1

Adipose tissue in the renal sinus

Differential Diagnosis

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

  1. Ratkal, V., Chawla, A., Mishra, D. K., & Krishna, S. (2015). Renal replacement lipomatosis of the right kidney. BML Case Reports, 6, 2015.Google Scholar
  2. Rha, S. E., Byun, J. Y., Jung, S. E., Oh, S. N., Choi, Y. J., Lee, A., & Lee, J. M. (2004). The renal sinus: Pathologic spectrum and multimodality imaging approach. Radiographics, 24(Suppl 1), S117–S131.CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Institute of Pathological Anatomy and HistopathologyPolytechnic University of the Marche Region (Ancona)AnconaItaly