Go back to clinical information and images

Diagnosis: Polyomavirus Associated Nephritis (with a secondary Crescent)

Glomerular crescent formation appears to represent a nonspecific response to severe injury, the initiating event is the development of physical gaps or holes in the glomerular capillary wall or Bowman's capsule (Ronco P. Mechanisms of glomerular crescent formation. In: UpToDate [Link (visited on 24th October 2016)]. In the presence of one or more crescents on a renal biopsy, we must consider the possibility of proliferative extracapillary GN, however, in cases of interstitial inflammation, the inflammatory rupture of the Bowman's capsule can generate formation of the crescent. This is a not uncommon finding in acute tubulointersticial cellular rejection. In our case, this alteration may be related to interstitial inflammation, however, the presence of cells with active replication of Polyomavirus in the crescent, evidenced by immunohistochemistry, leads us to consider the direct association of viral replication and cytopathic alteration with extracapillary proliferation. The association of polyomavirus and crescents has been previously described (Nickeleit V, et al. Polyomavirus infection of renal allograft recipients: from latent infection to manifest disease. J Am Soc Nephrol. 1999;10(5):1080-9 [PubMed Link]).

When the mechanism of formation of crescents is related to interstitial inflammation or Polyomavirus (and not glomerulonephritis) the extracapillary proliferation involves few glomeruli, it is not a diffuse alteration.

Visit the chapter: Kidney Transplantation Pathology of our Tutorial (only Spanish version).

Go back to clinical information and images

References

[Top]

Go back to clinical information and images