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Currently filtering by tag: Light chain proximal tubulopathy

Art of Medicine: Fanconi Syndrome

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Fanconi Syndrome
This painting shows the transition between a proximal tubule and the thick descending limb of the loop of Henle.  The proximal tubule has numerous functions, including transport of sodium chloride, bicarbonate, glucose, amino acids, organic cations, organic anions, and phosphate.  Disruption of proximal tubule function manifests clinically as Fanconi syndrome.   Development of polyuria, osteomalacia, muscle weakness, and growth failure can result if it is unrecognized and untreated. Fanconi syndrome can be diagnosed by clinical chemistry tests, including urine sodium, potassium, calcium, phosphate, glucose, amino acids, and uric acid levels, as well as urine pH.   In Fanconi syndrome, there is glycosuria...
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Diagnose This (February 25, 2019)

Article
What is your diagnosis?     ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​   ​   ​ ​  ...
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Art of Medicine: Light Chain Proximal Tubulopathy

Article
The painting above shows light chain proximal tubulopathy with crystals, which is one type of a monoclonal gammopathy of renal significance (MGRS).  MGRS, as defined by the International Kidney and Monoclonal Gammopathy Research Group, is a “clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin” (Leung N et al, 2019), and indicates end-organ damage resulting from a monoclonal gammopathy.   The most common MGRS manifestations include AL amyloidosis, monoclonal immunoglobulin deposition disease, light chain cast nephropathy, and light chain proximal tubulopathy.   In light chain proximal tubulopathy, a nephrotoxic monoclonal light chain induces acute tubular injury or proximal tubular dysfunction.  Proximal tubular...
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Light Chain Proximal Tubulopathy Without Crystals Tutorial

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The two most common morphologic variants of light chain proximal tubulopathy (LCPT) are LCPT with and without crystal formation. The histopathologic features of light chain proximal tubulopathy without crystal formation are shown here. (A) The tubular epithelium in this case shows evidence of acute tubular injury with reactive nuclei and cytoplasmic thinning (hematoxylin and eosin; original magnification × 400). (B) Transmission electron photomicrograph of proximal tubule cytoplasm showing lysosomes with an irregular mottled appearance and no evidence of crystal formation (unstained; original magnification × 20,000). (C and D) Serial sections stained with λ (C) and Κ (D) shows strong staining...
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Light Chain Proximal Tubulopathy Amyloid Proximal Tubulopathy Type

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The two most common morphologic variants of light chain proximal tubulopathy (LCPT) are LCPT with and without crystal formation. Two additional rare variants can also be seen, namely amyloid proximal tubulopathy and LCPT with fibrillary aggregates. The histopathologic features of amyloid proximal tubulopathy are shown here. (A and B) Proximal tubules have scattered cytoplasmic inclusions (arrows) that stain blue on (A) Masson trichrome stain and are (B) Congo red positive (original magnification × 400). (C) The cytoplasmic inclusions show lambda restriction (arrow) by immunofluorescence (fluorescein-conjugated anti-human lambda; original magnification × 400). (D) Transmission electron photomicrograph showing an aggregate in the...
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Light Chain Proximal Tubulopathy with Crystals

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The two most common morphologic variants of light chain proximal tubulopathy (LCPT) are LCPT with and without crystal formation. The histopathologic lesions of light chain proximal tubulopathy with crystal formation are shown here. (A) A case with dense crystal deposition resulting in a focally pale appearance to proximal tubules on periodic acid-Schiff stain (original magnification × 100). (B) Crystals are easily identified due to dark staining on Toluidine blue stain (original magnification × 400). (C) A light chain crystal (arrow) stains brightly fuchsinophilic on Masson trichrome stain in this case with rare crystal deposition (original magnification × 400). (D-F) Crystals can...
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Light Chain Proximal Tubulopathy

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Light chain proximal tubulopathy (LCPT) is a disease characterized by the renal biopsy finding of cytoplasmic light chain restriction within the proximal tubule cells. It has traditionally been known for the presence of Fanconi syndrome though this is not present in the majority of cases in more recent case series.1,2 There is a morphologic spectrum to the disease. Most notably, it can occur with or without crystalline inclusions in the proximal tubule cytoplasm. The photomicrographs here show lambda restriction in the proximal tubule cytoplasm in a case without evidence of crystal formation by light and electron microscopy. When there is evidence...
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Light Chain Proximal Tubulopathy Crystals

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This image shows the prominent intracytoplasmic tubular epithelial crystals characteristic of a subset of light chain proximal tubulopathy cases associated with Fanconi syndrome (normoglycemic glycosuria, aminoaciduria, uricosuria, hyperphosphaturia with hypophosphatemia). The crystals represent precipitated nephrotoxic monoclonal light chains, and unlike cases without crystals, pronase-digested immunofluorescence may be helpful in proving light chain restriction when routine immunofluorescence is negative. Light chain proximal tubulopathy with crystals indicates an underlying clonal plasma cell proliferation, and may be seen in patients with monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma, or lymphoma. Evidence of light chain cast nephropathy and/or monoclonal immunoglobulin deposition disease may also...
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Light Chain Deposition Disease and Light Chain Proximal Tubulopathy

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An elderly but previously healthy patient presents with weakness and fatigue and was found to have a creatinine of 3.0 mg/dl. His baseline Cr was 1.2 mg/dl four months prior. No history of diabetes or hypertension. Biopsy performed for kidney injury, acute versus chronic. Tubular Injury, interstitial fibrosis, and intact glomeruli. 1. Tubular Injury, interstitial fibrosis, and intact glomeruli 2. Linear staining for lambda light chains along tubular basement membranes 3. Negative staining for kappa light chains along tubular basement membranes 4. Positive Lambda staining in tubular droplets 5. Negative Kappa staining in tubular droplets Electron microscopy was negative for...
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Diagnose This! (June 5, 2017)

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What’s your diagnosis?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​   ​   ​ ​...
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Posted May 25th 2020
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