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Currently filtering by tag: Nephrocalcinosis

Nephrocalcinosis in Sarcoid

The renal biopsy in these photomicrographs shows tubular injury with increased interstitial calcium phosphate deposition.  Focal interstitial calcium phosphate can be a nonspecific finding in the setting of acute tubular injury.  However, the degree of deposition present in this biopsy is likely to be the pathologic driver of the kidney injury. The differential diagnosis would include nephrocalcinosis related to hypercalcemic conditions versus acute phosphate nephropathy secondary to exposure to high doses of phosphorus.  Nephrocalcinosis can occur in hypercalcemic conditions of any cause including sarcoidosis, milk-alkali syndrome, excessive vitamin D therapy, primary hyperparathyroidism, malignancy, and inherited tubulopathies such as Dent disease.

Diagnose This! (January 15, 2018)

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Calcium Phosphate Deposits

Calcium phosphate deposits within the kidney may be seen in the setting of hypercalcemia/ hypercalciuria or hyperphosphatemia/ hyperphosphaturia. Regardless of the etiology, the result is the formation of hydroxyapatite crystals within the tubular lumens (Fig 1 and 2), tubular epithelium, tubular basement membranes or within the interstitium. The term nephrocalcinosis is usually reserved to describe the presence of tubulointerstitial calcium phosphate deposits in patients with hypercalcemic disorders. These include, among others, hyperparathyroidism, sarcoidosis, underlying malignancies of various types, milk-alkali syndrome, hypervitaminosis A or D, Dent disease and other tubulopathies. On the other hand, phosphate nephropathy is predominantly seen in patients...