arrow-right-realarrow-rightarrow-rightback-to-topdoctordownloadfacebookinstagramlogologo-wordmarkcasttwitter
Close Modal

Blog


Currently filtering by tag: Chronic kidney disease

Twitter Poll (January 9, 2019)

ANSWER: C DNAJB9 immunohistochemical (IHC) stain is a quick and inexpensive tool used to confirm the diagnosis of Fibrillary GN. DNAJB9 IHC has a sensitivity of 98% and >99% specificity.   In 2017, Dr. Nasr et al. discovered a novel proteomic biomarker for Fibrillary GN called DnaJ homolog subfamily B member 9 (DNAJB9), which is a member of the chaperone gene family. DNAJB9 immunohistochemical (IHC) stain is a quick and inexpensive tool used to confirm the diagnosis of Fibrillary GN. DNAJB9 IHC has a sensitivity of 98% and >99% specificity.   Reference: Nasr S, et al. DNAJB9 is a specific...

Uromodulin

Welcome to our first post in the Art of Medicine series! In the hustle and bustle of busy clinics, labs, and hospitals we are often focused on the practical aspects of the practice of medicine. Dr. Tiffany Caza is the content creator for this series as well as being a renal pathologist and artist. Her art focuses on her interpretations of the histologic, cellular, and sub-cellular milieu where a dazzling variety of chemical and structural forces inherent to all life exist. In this series, she will be sharing her art (and occasionally others) and providing correlates to the science represented...

Where is the normal kidney tissue?

This kidney biopsy shows the histologic features characteristic of malakoplakia, which includes a dense, often obliterative, inflammatory infiltrate rich in histiocytes (Fig. 1 and 2) with numerous small intracytoplasmic concretions known as Michaelis-Gutmann bodies (these are best identified using histochemical staining for calcium as in Fig. 3). Malakoplakia is thought to result from chronic bacterial infection of the urinary tract (the most common causative organism is E. coli). Many cases are associated with the formation of small plaques and/or mass lesions. The bladder is the most common site of involvement, but kidney involvement occurs in about 15% of cases. The...

DNAJB9 helps uncover dual pathology…

This case illustrates the utility of immunohistochemical staining for DNAJB9, a recently described biomarker for fibrillary glomerulopathy (see reference).  The renal biopsy is taken from a 68-year-old man with a history of cirrhosis (cause unknown) who presents with mild microscopic hematuria, non-nephrotic range proteinuria, and chronic renal failure.  Glomeruli show diffuse mild mesangial matrix expansion.  Immunofluorescence shows granular mesangial IgA (2+) and smudgy mesangial and capillary wall IgG (2+) staining.  Electron microscopy (not shown) shows both immune complex-type and fibrillary deposits involving glomerular capillary basement membranes and mesangium.  Immunohistochemical staining for DNAJB9 shows mesangial staining.  Although IgA immunofluorescence staining may...

Not Quite Nodular

This biopsy came from a 70-year-old gentleman with acute renal failure. He had a known history of diabetes, hypertension, and chronic kidney disease.  His baseline serum creatinine is between 1.7 mg/dl and 1.9 mg/dl and was found to be elevated up to 2.9 mg/dl. Proteinuria was quantified as 0.2 g/g on urine protein to creatinine ratio.  Urinalysis showed trace blood and protein.  While processing the clinical information, one has to admit that this clinical presentation is not an unusual one.  A fair number of patients will have a decline in renal function that reflects the reality of an already struggling...

Membranous Glomerulopathy in Obesity-Related Glomerulopathy

The patient is a 57-year-old female, with a history of morbid obesity and persistent mild proteinuria (approximately 1 gm), who now presents with nephrotic syndrome and a UPCR of 10.5 g/g. Renal function is normal with a serum creatinine of 0.5 mg/dl. The biopsy shows marked glomerulomegaly with focal areas of perihilar segmental glomerulosclerosis (Fig 1 and 2). Additionally, the capillary loops appear mildly thickened, with frequent subepithelial fuchsinophilic deposits on trichrome stain and diffuse and global holes and spikes seen on silver stain (Fig 3). Immunofluorescence shows global capillary loop granular staining for IgG, C3, kappa, and lambda (Fig...

Proliferative Glomerulonephritis with Monoclonal IgG Deposits

This biopsy was performed on a 58-year-old female who presented with mild proteinuria. The glomeruli show diffuse and global endocapillary hypercellularity with segmental double contour formation of the capillary loops on the silver stain (Fig 1). Immunofluorescence shows mesangial and segmental capillary wall deposits positive for IgG (3+, Fig 2), C3 (3+, not shown), C1q (1+, not shown) and lambda light chain (3+, Figure 4). Staining for kappa light chain is negative in glomeruli (Fig 3). Further immunofluorescence staining for IgG subclasses proves the deposits to be IgG3 restricted. Electron microscopy shows mesangial and segmental subendothelial immune-complex type deposits. The...

Thyroidization

One of the many patterns of tubular atrophy in the kidney is the aptly named “thyroidization” pattern because of its resemblance to normal thyroid gland follicles. The dilated tubules contain abundant protein, resembling thyroid colloid, which is surrounded by flattened epithelial cells. This pattern of tubular atrophy is non-specific, although it is often more frequently encountered in the setting of chronic pyelonephritis and reflux nephropathy. Reference Lusco MA, Fogo AB, Najafian B, Alpers CE. AJKD Atlas of Renal Pathology: Tubular Atrophy. Am J Kidney Dis. 2016 Jun; 67(6):e33-4.

Nephronophthisis by Light Microscopy

Nephronophthisis is an autosomal recessive tubulointerstitial nephropathy that is a leading genetic etiology of end-stage renal disease in children and young adults. Approximately 60% of patients with a known genetic etiology of nephronophthisis are due to homozygous deletion of the NPHP1 gene. The histopathologic lesions associated with nephronophthisis are shown in these photomicrographs. (A) A tubular floret profile with complicated tubular branching in at least 4 directions (PAS; original magnification ×400). (B) Macula densa-like lesions (arrows) are tubular profiles in which there is a transition to a grouping of cells with crowded, hyperchromatic nuclei and a high nuclear: cytoplasmic ratio...

Smoking-Related Glomerulopathy

A renal biopsy was performed on this 52-year-old male with a history of hypertension and heavy tobacco use, who is being worked up for nephrotic range proteinuria and increased creatinine. The glomeruli (Fig 1 and 2) show nodular mesangial matrix expansion without definitive proliferation, necrosis or crescents. Focal areas of segmental glomerulosclerosis are present. There is no evidence of immune complex or monoclonal immunoglobulin deposition by immunofluorescence or electron microscopy. Of note, electron microscopy does show global thickening of glomerular basement membranes (not shown). While non-specific, the most common cause of nodular glomerulosclerosis in the United States is diabetes mellitus/glucose...