arrow-right-realarrow-right-whitearrow-rightback-to-topdoctordownloadfacebookinstagramlogo-markerlogo-wordmarkpodcastsearchsearch_whitetwitter
Close Modal

Blog


Currently filtering by tag: Amyloidosis

AL Amyloidosis

A 70 year-old female presents with nephrotic range proteinuria and a creatinine of 1.2. She was in her normal level of health until about 6 months ago when she noticed foamy urine and swelling in her ankles. She has lost 30 lbs unintentionally during the last few months. Her cardiologist said that her proteinuria does not appear to be related to the heart. A kidney biopsy is performed. The glomerulus in figure 1 is distorted and has a “washed-out” or pale appearance on PAS stain. A silver stain shows material which is non-argyrophilic (figure 2). A Congo red stain shows...

Twitter Poll (January 30, 2019)

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...

One little, two little, three little findings…

This biopsy came to us for evaluation of nephrotic syndrome. The patient is a Hispanic gentleman in his late 80s, with CKD stage IV and a history of arthritis, diabetes mellitus, coronary artery disease, and hypertension.  He had 4.9 g/g of proteinuria.  He had negative ANA, hepatitis B, and C serologies. C3 and C4 were within normal limits. Clinically, the differential diagnosis included membranous glomerulopathy and FSGS. The biopsy was a very good sample, consisting of long cores of renal tissue, mostly from cortex.  More than 20 glomeruli were present.  The glomeruli had clear features of diabetic nephropathy, as expected...

LECT2 Amyloidosis

The renal biopsy from this 79-year-old Hispanic male shows extensive glomerular, tubulointerstitial and vascular deposition of a PAS-pale (Fig 1), non-argyrophilic (Fig 2) and Congo red positive (Fig 3) amorphous material which shows apple green birefringence upon polarization, consistent with amyloid deposits. The amyloid deposits show no light chain restriction on immunofluorescence and electron microscopy shows numerous small, non-branching, overlapping fibrils within the glomeruli, interstitium, and vessels. An AA amyloid immunoperoxidase stain is negative; however, staining for LECT2 amyloid is strongly and diffusely positive (Fig 4). The aforementioned morphologic findings are characteristic of LECT2 amyloidosis. Although described relatively recently, it...

Congo Red Stain Tutorial

Positive Congo red staining in tissue with apple-green birefringence under polarized light is diagnostic of the presence of amyloid fibrils. Image A shows a glomerulus with Congo red positive mesangial staining while image B shows a renal biopsy with diabetic nephropathy that is negative for Congo red. Accurate interpretation of this stain hinges upon proper optimization so that there is elimination of nonspecific background staining.

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...

Diagnose This! (December 4, 2017)

What is your diagnosis?                ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​    ...

Twitter Poll (September 12, 2017)

Answer: C Amyloid fibrils typically measure 8-12 nm (answer C). The deposits seen in Immunotactoid glomerulopathy are composed by tubules ranging from 20-90 nm (answer A).  The deposits from Cryoglobulin and Fibrillary glomerulopathy vary from 10-30 nm (answer B). Fibronectin glomerulopathy consists of fibril deposits measuring 14-16 nm (answer D).

Pushing Glass (July 25, 2017)

The patient is a 64-year-old female who presents with 4.5 grams of proteinuria, hematuria, and a creatinine of 1.5. She has a history of hypertension and coronary artery disease. What is the best diagnosis? A. Arterionephrosclerosis B. Focal Segmental Glomerulosclerosis C. Amyloidosis D. Fibrillary Glomerulonephritis The best answer is C: Amyloidosis. The biopsy, at first glance, looks like a subcapsular scar with diffuse global glomerulosclerosis. In this setting, arterionephrosclerosis would provide a good explanation for this distribution of fibrosis especially with the severe arteriosclerosis seen in the vessel. FSGS is also a consideration and can produce segmental scars with extensive...