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What is your diagnosis? #DiagnoseThis #renalpath #nephropath

Today's #eyeSCANdy is an acellular scanning EM showing glomerular basement membrane duplication at high power in a glomerulus with a membranoproliferative pattern of injury.  Photo courtesy of Dr. Stephen Bonsib. #renal #pathology

A sample from the pathology teaching slide set on Anti-glomerular Basement Membrane (Anti-GBM) Antibody Glomerulonephritis, jointly prepared by Arkana Laboratories and @goKDIGO. #KDIGO #renalpath #kidneypath

This photomicrograph (PAS stain) shows a glomerulus with mesangial expansion by an acellular, PAS-pale, homogenous material consistent with amyloid. Further confirmation staining by Congo red shows positive staining within areas of amyloid deposition and apple-green birefringence on polarization. By immunofluorescence the amyloid deposits showed lambda light chain restriction making this an AL-type amyloidosis. #nephropath #renalpath

The silver impregnation stain is a key method of identifying basement membranes in human tissue, and its application in renal pathology is nearly universal. Notice in this image (Fig 1) how clearly demonstrating the capillary basement membrane using the silver stain allows one to distinguish cells within the capillary lumens from those “extracapillary” cells which are forming the glomerular crescent. In 1951, David B. Jones, MD, reported the development of a periodic acid silver reaction adapted specifically for the kidney which better highlighted basement membranes (American Journal of Pathology, Dec 1951: 991-1009). Most renal pathologists still rely heavily on the Jones stain in their daily diagnostic pathology practice and are grateful to the many contributions made by Dr. Jones to the field of renal pathology (Fig 2). #TeachingPoints #kidneypath #renal

ANSWER: B The target of the circulating ABBA autoantibodies is LDL receptor-related protein 2 (LRP2) also known as “Megalin”. ABBA is a rare autoimmune disease associated with acute kidney injury and tubulointerstitial damage. Histologically, IgG–positive immune deposits are found in tubular basement membranes by immunofluorescence (IF). When indirect IF is done using patient’s serum and normal kidney controls, there is reaction of the autoantibodies with the proximal tubular brush borders. REFERENCE: Larsen CP, et al. LDL-Receptor Related Protein 2 (Megalin) as a Target Antigen in Human Kidney Anti-Brush Border Antibody Disease. J Am Soc Nephrol, 2018; 29:644-653

#PathQuiz What is the name of the target antigen in anti-brush border antibody (ABBA) disease?

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Today's #eyeSCANdy is an acellular scanning EM showing glomerular basement membrane duplication from a glomerulus with a membranoproliferative pattern of injury.   Photo courtesy of Dr. Stephen Bonsib. #renal #pathology

A sample from the pathology teaching slide set on Lupus Nephritis, jointly prepared by Arkana Laboratories and @goKDIGO. #KDIGO #renalpath #kidneypath

The correct answer is Eosinophilic vasculitis. Read more here:

The photomicrograph is a high power PAS-stained section showing a glomerulus with focal segmental glomerulosclerosis, tip-lesion type. At 10 o'clock you can see a capillary loop becoming adherent to the take-off of the proximal tubule which also shows endocapillary foam cell formation and extracapillary protein resorption droplets. While the findings in this case are a bit more subtle than some, these are classic findings for focal segmental glomerulosclerosis, tip lesion type. This patient presented with abrupt onset of nephrotic syndrome and nephrotic range proteinuria with no significant past history of kidney disease. Clinically, focal segmental glomerulosclerosis, tip lesion type has the most favorable prognosis of all forms of focal segmental glomerulosclerosis and is frequently corticosteroid responsive. #nephropath #renalpath

A very common vascular histologic finding in patients with hypertensive nephrosclerosis is arteriosclerosis. In advanced lesions, such as this example, there is prominent intimal fibrosis with narrowing of the vessel lumen. The replacement of smooth muscle cells in the tunica media by fibrous tissue is thought to result from collagen and elastic tissue synthesis by myointimal cells. The degree of intimal fibrosis is thought to be more closely associated with elevated blood pressure than the degree of hyaline arteriolosclerosis. #TeachingPoints #kidneypath #renal

ANSWER: B The medulla is the only compartment affected by AAPOAIV amyloidosis, sometimes with large amounts of amyloid. Glomeruli and vessels are spared and not affected by this type of amyloid. AAPOAIV Amyloidosis is a systemic amyloidosis reported from wild-type apolipoprotein AIV. When the kidney is involved the patient presents with gradual loss of renal function and proteinuria. It may also have cardiac involvement. References: Sethi S, Theis JD, Shiller SM, et al. Medullary amyloidosis associated with apolipoprotein A-IV deposition. Kidney Int 81: 201–206, 2012. Dasari S, Amin S, Kurtin P, et al. Clinical, biopsy, and mass spectrometry characteristics of renal apolipoprotein A-IV amyloidosis. Kidney Int 90: 658-64, 2016.