Case 18: Additional Pathology

Case 18 Index

Let’s take a look at the H&E stain.
Renal Medullary Angiitis in ANCA

What do you see?
Endocapillary proliferation with obliteration of the capillary loops
Oops! We don’t see any capillary loops here…try again!
Subendothelial deposits
 Deposits are best visualized under electron microscopy (EM)
Acute interstitial nephritis
We do see some inflammatory cells in the interstitium here, but there’s a more accurate description of what see. Take another shot!
Medullary angiitis
Excellent! We see hemorrhage into the interstitial space with infiltration of polymorphic neutrophils. This finding should bring you one step closer to our final diagnosis here.
The immunofluorescence for IgA, IgM, IgG, and C1q are ready for you and look pretty similar. What do you see in this representative image below?
Granular basement membrane staining of IgG
The basement membrane does not seem to be a bright green color here. Try again!
“Full house” staining
“Full house” staining refers to granular basement membrane/mesangial staining of IgG, IgA, IgM, C3, and C1q – typically seen in SLE nephritis. We only see
Negative IF
Great! This is a negative IF image and should guide us to the final diagnosis.
Mesangial staining of IgA
The mesangial space does not appear bright green here, thus there is no IgA staining here. Pick again!

Click here if you’re confident in your final diagnosis!

Case 18 Index
Case 18 Introduction
Case 18 Physical Exam

Case 18 Diagnostic Testing
Case 18 Pathology