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Currently filtering by tag: Rare renal disease

Ask-Upmark

This kidney biopsy is from a 16-year-old boy with a history of chronic reflux nephropathy. Imaging findings showed unilateral segmental cortical scarring. Although regions of the biopsy show intact renal cortex with normal appearing glomeruli and tubules (Fig. 1), well-demarcated adjacent cortical segments are aglomerular and show severe tubular dropout and interstitial fibrosis (Fig. 2). No definite dysplastic features are noted. This pattern of renal injury supports the clinical impression of unilateral segmental renal hypoplasia (Ask-Upmark kidney). Vesicoureteral reflux is thought to be the main cause of injury in an Ask-Upmark kidney. The condition was first described by the Swedish...

Diagnose This! (February 12, 2018)

What is your diagnosis? (Congo red is negative as is routine immunofluorescence)     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​...

Fibronectin Glomerulopathy

A renal biopsy was performed in a 32-year-old female with microscopic hematuria and nephrotic range proteinuria of 4 grams per day. Serologic workup for autoimmune disease was negative. The glomeruli show extensive mesangial and subendothelial deposition of PAS-positive (A) and silver-negative material (B and C) by light microscopy. The immunofluorescence showed segmental glomerular staining for C3 (1-2+). An immunoperoxidase stain for fibronectin was diffusely positive in glomeruli (D) and electron microscopy showed massive electron dense deposits replacing the mesangium that were also present along the subendothelial aspect of basement membranes (E). These findings are consistent with fibronectin glomerulopathy. Approximately 40%...

Fabry Disease in Female Carriers

A renal biopsy was performed on a 51 year old female with strong family history of Fabry disease and a known carrier of an alpha-glycosidase gene (GLA) pathogenic variant. At the time of the biopsy, the patient had no renal or extrarenal manifestations. The biopsy shows glomeruli with prominent visceral epithelial cells (podocytes) displaying ample vacuolated cytoplasm (Fig 1, H&E; Fig 2, Jones). Furthermore, electron microscopy shows numerous large, lamellated lipid vacuoles (myeloid bodies or zebra bodies) within the podocytes, characteristic of Fabry disease (Fig 3). Fabry disease is an X-linked disorder caused by GLA mutation and the resulting deficiency...

Amyloid Cast Nephropathy

Cases of light chain cast nephropathy occasionally show amyloid staining properties including positive staining for Congo red with green birefringence upon polarization. The significance of this staining in light chain casts is largely undetermined though, when present, it is sometimes referred to as “amyloid cast nephropathy”. A recent case series found that that intratubular amyloid was significantly associated with the occurrence of systemic light chain amyloidosis (5/13 in the 'intratubular amyloid' group vs 0/30 in the 'no intratubular amyloid' group, P=0.001). Thus, when present in light chain cast nephropathy, a work-up to examine for the possibility of systemic disease is...

Fibrinogen Aα-chain Amyloidosis

A 65-year-old male, with no significant past medical history, presents with proteinuria and worsening renal function. The serum creatinine is 2.4 mg/dl and the UPCR is 2.5 g/g.  Serum and urine protein electrophoresis with immunofixation shows the absence of monoclonal immunoglobulin.  Free serum light chain ratio is within normal limits.  Remaining of serologies are also negative/normal.  A renal biopsy was performed and representative images are shown (Fig 1-5).  The glomeruli are markedly enlarged and show massive deposition of PAS-pale (Fig 1), weakly argyrophilic (Fig 2), Congo red positive (Fig 3) amorphous material which shows apple green birefringence upon polarization (Fig...

Apolipoprotein A-IV Amyloidosis

This renal biopsy from a 71-year-old female, who presented with progressively worsening renal failure, shows unremarkable glomeruli by light microscopy (Fig 1), with minimal associated tubulointerstitial chronic injury. Of note, multifocal PAS-pale, weakly argyrophilic, Congo red positive (Fig 2) deposits with apple green birefringence (Fig 3), consistent with amyloid deposits, are present exclusively within the interstitium of the renal medulla. No amyloid deposition is present within the renal cortex or involving vascular structures.  The deposits show no light chain restriction by routine or paraffin immunofluorescence (not shown), making the possibility of light chain-type amyloidosis unlikely.  Furthermore, an immunoperoxidase stain for...

Embryonal Hyperplasia of Bowman’s Capsule Epithelium

H&E and PAS-stained sections from the kidney of an 8-year-old male with advanced nephrosclerosis of unknown etiology. An exuberant proliferation of epithelial cells with an embryonal or immature appearance, arranged in a tubular and nodular pattern, is seen surrounding globally sclerotic glomeruli.  This unusual finding termed “embryonal hyperplasia/metaplasia of Bowman’s capsule epithelium” has been described in patients with end-stage renal disease on long-term dialysis. More recently, this finding has also been associated with WT1 mutations in patients with Denys-Drash syndrome and isolated diffuse mesangial sclerosis. The clinical significance of this finding is yet to be determined. References: 1. Hughson MD,...

Sclerosing Peritubular Nodule

Today’s teaching point is a true “zebra” in renal pathology. The arrows in the light microscopic image identify what have been called renal sclerosing peritubular nodules, which are foci of peritubular spindle cells with myofibroblastic differentiation and variable amounts of collagen formation. They are found in patients with neurofibromatosis type 2 (NF2). The black and white clinical photograph, in contrast, shows a patient with neurofibromatosis type 1 (NF1), in which renal sclerosing peritubular nodules have not been described. The etiology, classification, and clinical significance of these nodules remain unclear. Gökden N et al. Renal sclerosing peritubular nodules in a patient...