Kuang-Yu Jen, MD, PhD

Professor, Department of Pathology, Director of Renal Pathology, UC Davis Medical Center, @UCDPath, @UCDavisHealth, #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Long weekend often brings urgent cases. Here is one that was STATed, ended up showing anti-GBM GN. Diffuse crescents (nearly 100%). Linear IgG. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Unfortunately, great cases are almost always not good for the patient. This one has light chain cast nephropathy and deposition dz. PAS-weak casts with cellular reaction. Super bright kappa (lambda neg). Powdery electron-dense material along TBM and mostly mesangium #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@GersonPaull_MD @musamapath It can happen not uncommonly in my experience. But the trend is to be more aggressive in using even suboptimal kidneys since it at least gives some of the older patients a chance to come off dialysis.

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Deceased donor biopsy with prominent ATI, some areas of frank tubular necrosis, and collapsing glomerulopathy likely due to ischemia. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Not sure why a flood of AA-amyloid from heroin users recently. 3 cases in the last month! IHC is SAA. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@JZRenalPath Surprisingly, no! Also, other side only had minimal nonspecific changes, not even much ATI. Need to talk to surgeon to get more insight. Maybe some upstream thrombotic event in a larger vessel?

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@JZRenalPath This is FFPE on frozen remnant from procurement.

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Super subtle case of AL-amyloid. I like the combo of IF and LM polarization on Congo red. Very focal amyloid on EM. IF showed rare foci of weak mesangial lambda-restricted staining, correlating to patient's paraproteinemia. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@ShuchiGulati Yes we saw several down in San Francisco and published about levamisole. Have not seen that much up here in Sacramento. Possible meth is more drug of choice (at least according to my wife who is an ER doc).
https://t.co/jyh8d7qcEy

[Kuang-Yu Jen, MD, PhD @KidneyPath]

AA-amyloid due to IV drug use. We get a good number of these in Northern California, but prevalence depends on location. Possibly related to type of heroin (black tar in particular). #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

My first cardiac biopsy post. Not sure if #CardiacPath is the right tag. AL-amyloid in heart with kappa restriction (lambda completely negative). Amorphous light pink material in between muscle fibers. Congo red positive.

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Urate within the medulla of someone with gout. Crystals washes out with FFPE but happened to catch one on IF frozen sections. Amorphous material can be seen on FFPE sections as well. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@roboonya The vessel looks like it has hyalinosis on special stains.

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Examples of acute T cell-mediated rejection findings: tubulitis and endotheliitis. This case had a good number of eosinophils, but patient history of non-compliance and endotheliitis (no abx use) strongly favors rejection rather than drug allergy #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Nice example of chronic active antibody-mediated rejection with transplant glomerulopathy (and severe arteriolar hyalinosis from years of CNI use). Plenty of double contours and glomerulitis! #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

I feel like I keep getting great examples of anti-VEGF-induced TMA. Here is one w/ nice EM showing prominent subendothelial widening with flocculent material and new GBM formation. LM with capillary lumen closure, fragmented RBCs, and GBM reduplication. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@sam_albadri Just frozen, but very good signal

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Older individual with monoclonal gammopathy, proteinuria, worsening renal function. On bx, widespread eosinophilic crystalline inclusions in proximal tubules, kappa-restricted on IF. EM with abundant rhomboid crystals. Light chain proximal tubulopathy. #RenalPath

[Kuang-Yu Jen, MD, PhD @KidneyPath]

@SwethaKanduriMD Not much clinical info except kappa restriction on SPEP. Nephrotic range proteinuria. No apparent Fanconi.

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Good article pointing out some unique findings in such cases: https://t.co/O2YJHa2XS6

[Kuang-Yu Jen, MD, PhD @KidneyPath]

Another bevacizumab-related (anti-VEGF) glomerulopathy. Many classify this as a "chronic TMA" pattern (note the extensive double contours), although it has it's own unique features that is not typical of TMA, like the hyaline thrombi/aggregates. #RenalPath