Case 41: Pathology

Case 41 Index

Excellent work, your patient tolerated the kidney biopsy well. You review the initial light microscopy with the pathologist.  Click here for a pathology 101 refresher.

So, what’s the stain here?
Jones Methamine Silver stain
Nailed it!
Periodic-Acid Schiff (PAS) stain
Under the PAS stain, the basement membranes should appear a magenta-ish color. Try again!
Hematoxylin & Eosin (H&E) stain
We shouldn’t see black staining of the basement membrane with the H&E stain.
Masson’s Trichrome stain
This stain is used to look for fibrosis, but that’s not what we see here. Think blues and reds for this stain. Pick again!

Which of the following do you see above in this Jones Methamine Silver stain?
Collapsing glomerulus
Yes! We see collapse of the glomerular capillary loops above.
Focal segmental glomerulosclerosis tip lesion
Close, but we don’t see a sclerotic lesion here involving the proximal tubule pole.
Minimal change disease
Look a little closer – there are major changes here!
Podocyte effacement
The podocyte structures are best visualized under electron microscopy, not light microscopy. Try again!
Thrombotic microangiopathy (TMA)
Hmm, we don’t see evidence of TMA here – this would include intravascular fibrin thrombi, double contours of the glomerular basement membrane, and intimal proliferation of the arterioles. Pick again!
Double contours of the glomerular basement membrane (GBM)
We don’t visualize any double contouring of the GBM here, pick again!

Your pathologist shows you the electron microscopy (EM). What do you see here (more than one may be correct)?
Podocyte effacement
Correct! The podocytes are effaced here. Take a look at this comparison to normal kidney tissue (bottom image):
Tubuloreticular inclusion
Correct! This is a tubuloreticular inclusion (TRI) in an endothelial cell, commonly found in autoimmune diseases and viral infections.
Mesangial deposits
We do not see electron-dense deposits in the mesangium here. Try again!

Click here once you are confident in your final diagnosis!

Case 41 Index
Case 41 Introduction
Case 41 Physical Exam
Case 41 Diagnostic Testing