Medical Renal

Question 1

What is the preferred stain for renal?

Answer 1

PAS, not really H+E

Question 2

How many cells should mesangial areas have?

Answer 2

1-3

Question 3

Hypercellularity - where to look in the glomerulus

Answer 3

In the urinary space

In the capillary loops

In the mesangial space

Question 4

Tubules in the kidney should be. . .

Answer 4

Back to back with a barely discernible interstitium

Question 5

Proximal vs distal tubules

Answer 5

Proximal: grainy brush border, best seen on PAS, cuboidal-to-columnary epithelium, lumen not very visible (filled by brush border)

Distal: More cuboidal with clearer cytoplasm, more evident lumen

Question 6

Evaluating proximal tubules

Answer 6

1. Distended/enlarged?
2. Back-to-back, or separated?
3. Brush border visible?
4. Epithelium flattened or denuded?

Question 7

Vessels in the kidney

Answer 7

Assess for atheroclserosis and vasculitis

Question 8

3 components of microscopic kidney exam

Answer 8

1. Glomeruli
2. Tubulointerstital space
3. Vessels

Question 9

Answer 9

Diabetic nephropathy

Kimmelstein-Wilson nodules, characteristic of diabetic nephropathy (if the patient doesn’t have diabetes, we’d just call it nodular mesangial expansion) – the expansion/matrix deposition is caused by response to endothelial and mesangial cell injury. Nodules are positive on Jones silver stain.

Note the interstitial thickening and separation of the tubules as well. Tubules are atrophic. Vessels display hyalinosis, sometimes with near complete occlusion.

Answer 10

Ig deposition disease

IF/EM help to differentiate from diabetic nephropathy.

Answer 11

Renal oxalosis / crystal nephropathy

Dischevled tubular brush border, dark material lining tubule lumen. Flattened epithelium. Distension.

Polarizable calciium oxalate crystals in the tubules.

Can occur after bariatric surgery due to poor Ca absorption. Turmeric supplements can cause this too, nut-restricted diet, ethylene glycol toxicity.

Answer 12

Glomerular and vascular PAS-pale material which is also Jones stain negative – amyloid.

Question 13

Fluorescent stains for amyloid typing

Answer 13

Kappa
Lambda
Amyloid A
Transthyretin

Question 14

Answer 14

Cresecentic Glomerulonephritis

Pathologic correlate of the clinical entity rapidly progressive glomerulonephritis (RPGN).

Filling of the urinary space with inflammatory cells.

Stages:
1. Fibrinoid necrosis
2. Cellular crescent
3. Fibrous crescent

Some disease have uniform progression (anti-GBM), some have glomeruli in various stages of remodeling (ANCA).