Nephrotic range proteinuria: rare manifestation of scleroderma renal crisis.

The nephrotic range of proteinuria is uncommon in scleroderma renal crisis. This 46-yr-old woman with a medical history of scleroderma presented with very high blood pressure, a sudden elevation of serum creatinine, and proteinuria in the nephrotic range. Renal biopsy revealed onion-skin type of arterial changes with necrosis, confirming the presence of scleroderma nephropathy. Electron microscopy showed diffuse fusion of foot processes. Immunohistochemical staining (IHC) revealed increased expression in glomeruli of phosphorylated mammalian target of rapamycin (p-mTOR). These findings suggest that fusion of foot processes and activation of mammalian target of rapamycin-dependent pathways in podocytes are most likely responsible for the severe proteinuria in this patient with scleroderma nephropathy.