[Ultrastructure of glomerular podocyts in the incipient phase of minimal change nephrotic syndrome with thin basement membrane disease].

An 80-year-old woman was referred to the Division of Nephrology at Ehime University Hospital because of leg edema in December 2010. She had been treated with 300 mg of tocopherol for scleroderma since 2007 and treated with 9 mg of prednisolone (PSL) for autoimmune hearing loss since 2010. Due to the occurrence of mild hematuria (5-9/HPF), proteinuria (0.9 g/day) and an increased serum creatinine level (1.31 mg/dL), a renal biopsy was performed. Light microscopy (LM) showed minor abnormality in the glomeruli, and immunohistology showed the absence of deposits of immunoglobulins and complements. Electron microscopy (EM) showed a thin glomerular basement membrane with a limited level of podocyte abnormalities. Due to the findings of intimal thickening of interlobular arteries and subcapsular accumulation of global sclerosis on LM, she was diagnosed with nephrosclerosis and thin basement membrane disease. Four weeks later, her leg edema had increased considerably and urinary protein had increased to 12.4 g/day. The second biopsy showed similar findings in LM and IF as the first biopsy, but EM revealed diffuse foot process effacement. She was diagnosed with minimal change nephrotic syndrome (MCNS) and treated with methylprednisolone pulse therapy followed by 40 mg of oral PSL. Her urinary protein had completely disappeared 6 weeks later. Complete remission with PSL treatment indicates that urinary protein at first renal biopsy was due to MCNS. Our case exhibited podocyte features in the incipient phase of human MCNS.