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Thrombotic Microangiopathy

Thrombotic Microangiopathy
This biopsy is from a person in their 40’s, who presented with accelerated hypertension and blood pressure of 240/180 mm/Hg. Urinalysis showed 2+ protein and 2+ blood and his serum creatinine was 7.2 mg/dl. Further workup revealed a low platelet count at 90,000 and schistocytes on peripheral smear. He was admitted to the ICU where careful hypertension management was instituted. Serologies were negative for ANA, cANCA, pANCA, anti-GBM, and hepatitis B and C. Complements were normal. ADAMTS-13 was normal. Diagnosis: Thrombotic Microangiopathy Global Glomerulosclerosis (20/72). Interstitial Fibrosis, Severe. Arteriosclerosis and Arteriolar Hyalinosis, Severe. Discussion: Thrombotic microangiopathy is a pattern that...

Light Chain Deposition Disease

renal cortex from renal biopsy showing Light Chain Deposition Disease
An elderly patient presents to nephrology for a rising creatinine. Baseline creatinine was 2.1 mg/dl six weeks prior but is now 3.4 mg/dl. He has poorly controlled diabetes and moderately well-controlled hypertension. Work up revealed a MGUS with positive IgG Lambda. Biopsy performed for kidney injury and to determine if there is a renal component related to his MGUS (r/o MGRS). Electron microscopy revealed only irregular electron densities along the tubular basement membranes. No powdery deposits were found. Diagnosis: Immunofluorescence Features Suggestive of Light Chain Deposition Disease, Lambda Light Chain Type Interstitial Fibrosis, Mild Arteriosclerosis, Severe   Follow Up: Bone...


An adult patient in the mid-fifties with a deceased donor renal transplant for three years (primary disease “hypertensive nephrosclerosis”) presented with a low-grade fever and a rising creatinine. Urinalysis showed hematuria and proteinuria. A transplant biopsy was performed. 1. Low power showing one relatively intact core and a second core showing diffuse replacement of the usual renal parenchyma by inflammation and fibrosis (Trichrome, 40x) 2. Mixed inflammatory cell infiltrate (Jones Silver, 400x) 3. Macrophages with PAS-positive granules (PAS, 400x) 4. Michaelis-Gutmann body (H&E, 400x 5. Michaelis-Gutmann body (H&E, original magnification 600x) 6. Von Kossa Positive Michaelis-Gutmann bodies (von Kossa, 400x)...

Light Chain Deposition Disease and Light Chain Proximal Tubulopathy

Light Chain Deposition Disease
An elderly but previously healthy patient presents with weakness and fatigue and was found to have a creatinine of 3.0 mg/dl. His baseline Cr was 1.2 mg/dl four months prior. No history of diabetes or hypertension. Biopsy performed for kidney injury, acute versus chronic. Tubular Injury, interstitial fibrosis, and intact glomeruli. 1. Tubular Injury, interstitial fibrosis, and intact glomeruli 2. Linear staining for lambda light chains along tubular basement membranes 3. Negative staining for kappa light chains along tubular basement membranes 4. Positive Lambda staining in tubular droplets 5. Negative Kappa staining in tubular droplets Electron microscopy was negative for...

IgAN and Acute Tubular Injury with Legionella

Acute Tubular Injury with Legionella
Acute kidney injury in the setting of Legionella pneumonia. This biopsy is a middle-aged person with Legionella pneumonia who developed acute kidney injury. Early in the hospitalization, the baseline creatinine was 1.0 mg/dl. However, the creatinine rose to 6.5 over 5 days and Nephrology was consulted. Urinalysis showed microscopic hematuria and 2+ proteinuria. The creatinine increased to 7.5 and a biopsy was done. Serologic studies were ordered and were pending at the time of biopsy. The images provided show a combination of acute tubular injury (Image 1), mild mesangial matrix expansion (Image 2) and mesangial IgA deposits (Image 3). While...

BK Nephritis

BK virus in renal biopsy at Arkana Laboratories
This biopsy is from a patient with ESRD due to polycystic kidney disease. He is s/p deceased donor renal transplant 11 months prior to this biopsy. He was noted to have a steadily rising creatinine from baseline of 1.3 mg/dl up to 4.6 mg/dl at biopsy. Note the severe interstitial inflammation with nuclear atypia and severe arteriosclerosis (Figure 1, H&E 100x). There are markedly atypical nuclei including an apoptotic body (arrowhead) seen in the second image (Figure 2, 400x). The third image shows an SV40 IHC stain for polyoma virus that is positive in many nuclei (Figure 3, IHC SV40...

Fibrillary Glomerulopathy

Fibrillary Glomerulopathy
Commonly heard after we give the diagnosis: “I heard about this in Fellowship”… This 62-year-old African-American just completed treatment for hepatitis C with HARVONI® (ledipasvir 90 mg/sofosbuvir 400 mg). He was found to have an elevated creatinine of 1.8 mg/dl (baseline 1.1 mg/dl). Urinalysis showed 3+ protein with no blood and no casts. He also has well-controlled hypertension for more than 10 years. 1. Glomerulus with diffuse mesangial expansion (PAS x400) 2. IgG predominantly mesangial but with extension into loops (200x) 3. Mesangial and loop fibrillary deposits (EM 4,000x) 4. Mesangial and loop fibrillary deposits (EM 12,000x.) Diagnosis: Fibrillary Glomerulopathy

Diabetic Nephropathy

Protein Insudative Lesions in Diabetic Glomerulopathy Diffuse and nodular glomerulosclerosis is the classic appearance of diabetic glomerulopathy. However, diabetic nephropathy also includes so-called insudative lesions including “Fibrin Caps” and “Capsular Drops”. These lesions are characteristically seen in diabetics with nephrotic range proteinuria and are thought to be the result of ‘insudation’ of protein and other serum products into the space between the cell lining and its supporting basement membrane. In the case of the Fibrin Cap, the lesion is seen between the endothelium and the glomerular basement membrane (Blue Arrows, Jones Silver 400x). Fibrin cap is a misnomer because there...

IgG Background Staining in Diabetic Nephropathy

Immunofluorescence staining with IgG in a patient with diabetic nephropathy shows enhanced linear staining along the glomerular basement membranes and all other basement membranes. This includes the tubules and Bowman’s capsule. It also highlights the mesangial nodules. This is non-specific and not to be confused with anti-glomerular basement membrane antibody disease (anti-GBM, also called Goodpasture Syndrome). Diabetic staining is 1+ to 2+ and distributed along all basement membranes. If anti-GBM is also present in diabetic nephropathy, the IgG will be 3+ along the GBMs and the other basement membranes will have the background 1+ to 2+ staining. Sometimes this is...