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Currently filtering by tag: Fanconi syndrome

Art of Medicine: Fanconi Syndrome

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...

Light Chain Proximal Tubulopathy Amyloid Proximal Tubulopathy Type

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...

Light Chain Proximal Tubulopathy Crystals

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...

Diagnose This! (June 5, 2017)

What’s your diagnosis?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​   ​   ​ ​...