Case 20: Pathology

Case 20 Index

Excellent work, your patient tolerated the kidney biopsy well. With rejection on the differential you ask the lab to rush the results, and that afternoon your pathologist shows you the H&E.  Click here if you want some quick pathology tips.

HS18-29051 HE0001

HS18-29051 HE0002

Which of the following do you see above (more than one may be correct)?
Inflammatory infiltrate in interstitium
Yes! We see collections of inflammatory cells (look for the dark blue clusters) in the interstitial space.
Podocyte effacement
The podocyte structure is best visualized under electron microscopy, not light microscopy, and there are no glomeruli to assess here.
Intranuclear inclusions
That’s right! The zoomed in image above demonstrates intranuclear basophilic viral inclusions.
Cytoplasmic inclusions
There are inclusions here (best visualized in zoomed in image), but they do not appear to be within the cytoplasm. Try again!
Crescentic glomerulonephritis
We don’t have any glomeruli to assess here.


Your pathologist has enough sample left to run one more test. Which will it be?
Electron microscopy (EM)
Given the findings above, EM is unlikely to provide additional information to make this diagnosis. However, inclusions are often also well seen on EM.
Simian Virus 40 (SV-40) stain
Great choice! Here it is:
Immunofluorescence (IF)
Given the findings above, we don’t usually need IF to make this diagnosis. We would expect the IF stain to be negative.
Time to lock in your final diagnosis!
Cytomegalovirus (CMV) infection
Acute cellular rejection (ACR)
Antibody-mediated rejection (AMR)
Recurrent FSGS
Tacrolimus toxicity
BK virus nephropathy (BKVN)
Acute interstitial nephritis (AIN)
Post-transplant lymphoproliferative disorder (PTLD)
Hypertensive nephropathy
Obstructive uropathy

Click here once you are confident in your final diagnosis!

Case 20 Index
Case 20 Introduction
Case 20 Physical Exam
Case 20 Diagnostic Testing