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Archive: April 2017

Necrotizing Vasculitis

Necrotizing Vasculitis as seen with Silver Methenamine Masson’s Trichrome (SMMT) stain on a renal biopsy. The immunofluorescence panel was negative (pauci-immune). Renal biopsies contain small arteries and thus this is consistent with granulomatosis with polyangiitis (GPA). The biopsy was obtained from an 87-year-old male who presented with hematuria, proteinuria and a creatinine of 2.5 mg/dl. Following the biopsy, ANCA serologies were ordered and cANCA positivity was found.

Lab Week

Today is the last day of Lab Week! With celebration, often comes treats. Our lab team decided to hit the kettlebells today to make up for all the sugary goodness that was consumed.

Proliferative Glomerulonephritis with Monoclonal IgG Deposits

The glomerulus pictured for light microscopy shows membranoproliferative changes with mesangial hypercellularity, GBM duplication, and endocapillary proliferation. There is light chain-restricted staining for IgG kappa by immunofluorescence. The deposits were immune complex-type by electron microscopy (not pictured). The findings in this biopsy are consistent with the entity known as proliferative glomerulonephritis with monoclonal IgG deposits. A case series detailed the clinical findings in 37 patients with proliferative glomerulonephritis with monoclonal IgG deposits and found the underlying etiology was undetermined in the majority of cases. Most did not appear to be related to infection, autoimmune-related disease or hematologic malignancy (see reference below)....

Anti-Glomerular Basement Membrane

A 19-year-old Caucasian male patient presented with acute renal failure. Serum creatinine was 4.9 mg/dL and he had hematuria and non-nephrotic range proteinuria. Anti-GBM serologic testing was positive. No ANCA detected. Figure 1 one shows a cellular crescent filling Bowman’s space. Figure 2 also shows a cellular crescent associated with a prominent break in Bowman’s capsule (red arrow). Immunofluorescence shows global linear IgG staining of the capillary walls (Figure 3).

Oxalate Nephropathy

H&E stained section (Fig. 1) demonstrating acute tubular injury with frequent translucent intratubular crystalline deposits on a background of severe tubulointerstitial scarring. The crystals show birefringence under polarized light (Fig. 2) characteristic of renal oxalosis. After the biopsy, this 60-year-old male admitted consumption of small quantities of ethylene glycol over the past 16 months.  Other causes of secondary renal oxalosis include enteric forms (Crohn’s disease, celiac sprue, pancreatic insufficiency, small intestinal or gastric bypass or resection), over-ingestion of oxalate containing foods (e.g., dark leafy vegetables, rhubarb, kale, starfruit, tea, spinach, sesame seeds, almonds, peanuts, beets, buckwheat flour, chocolate soy milk),...

Diagnose This! (April 24, 2017)

What is the finding shown and what disease does this likely represent?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​...

Arkanines: Truman

Meet Truman! He belongs to our director, Dr. Walker (and our real boss, Mrs. Gail). Truman enjoys going to daycare, playing in a mud pit, eating chicken jerky, and having goat's milk on top of his dog food.

Myoglobin Casts

A 54-year-old man with a history of hypertension and hypercholesterolemia presented with complaints of generalized “muscle stiffness” and cola-colored urine. He was found to have markedly elevated serum creatinine and creatine kinase levels. A renal biopsy showed acute tubular injury with numerous pigmented casts (Fig 1), which were proven to be myoglobin casts by immunohistochemistry (Fig 2). The etiology of the patient’s myoglobinuria was thought to be statin medication, the dose of which had recently been increased. Here is a link to a recent article describing the morphologic spectrum of myoglobin casts in renal biopsies:https://www.ncbi.nlm.nih.gov/pubmed/?term=27038680.

Pushing Glass (April 18, 2017)

A 45 year-old man received renal transplantation for HCV-associated end stage renal disease. He is currently treated with Sofobuvir, Tacrolimus and ACEI. He developed renal function impairment (Serum Cr increased to 2.3 mg/dL) with mild proteinuria. Based on the renal biopsy images, which is the most likely diagnosis? A. Severe acute tubular injury due to Sofobuvir B. Calcineurin inhibitor toxicity C. Polyomavirus nephropathy D. Tubular injury secondary to cryoglobulinemia E. Diabetic nephropathy     The answer is B. The light microscopic examination demonstrates isometric vacuolization of tubular epithelial cells, severe hyaline arteriolopathy and a striped pattern of fibrosis. These features...

Diagnose This! (April 17, 2017)

What is this stain and what does this finding mean in a transplant patient (Hint: It’s not a vascular marker).     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​...