Sunitinib induced nephrotic syndrome and thrombotic microangiopathy

Abstract

Sunitinib is an oral, multitargeted receptor tyrosine kinase inhibitor of targets such as vascular endothelial growth factor and platelet derived growth factor receptor. It is used for the treatment of metastatic renal cell carcinoma (RCC). Use of sunitinib has been associated with renal dysfunction and nephrotic syndrome. However, simultaneous occurrence of nephrotic syndrome and renal dysfunction in a patient treated with sunitinib is rare. We report a case of metastatic RCC treated with sunitinib for 22 months who presented with nephrotic syndrome and renal dysfunction. Renal biopsy was diagnostic of thrombotic microangiopathy with diffuse effacement of podocytic foot process.

Keywords: Nephrotic syndrome; receptor tyrosine kinase inhibitor; sunitinib; thrombotic microangiopathy.

Figure 1

Glomerulus showing accumulation of plasma-like material in the widened subendothelial area globally (star mark). One of them shows presence of red blood cells in the microaneurysmal space (black arrow) at the tubular pole (×40, periodic acid-schiff methenamine silver stain)

Figure 2

Ultrastructure of glomerular capillary wall revealing marked widening of the subendothelial spaces by electron-lucent material (star mark) and fibrin tactoids (white arrow). New basement membrane layer is seen on the inner aspect. Overlying podocytes show diffuse effacement of foot processes (×9300, uranyl acetate and lead citrate)