Intramembranous electron-dense deposits in a nephrotic patient with mixed connective tissue disease: unusual response to corticosteroid therapy

A 56-year-old female patient, who had had minor change nephrotic syndrome (MCNS), was referred to us because of a fever and a massive proteinuria. Six years before, she had first noticed leg oedema, leading to the detection of nephrotic-range proteinuria. The diagnosis of MCNS at that time was based on minor glomerular abnormality by the light microscopy examination. She had then been treated with corticosteroid, after which her proteinuria had promptly disappeared. Her corticosteroid had then been gradually withdrawn, and no relapse had occurred for 6 years. At her first visit with us, she had a fever and sclerodactylia as well as swollen hands and Raynaud’s phenomenon, and laboratory examinations showed a high titer of anti-nuclear and anti-RNP antibodies, resulting in a diagnosis of mixed connective tissue disease (MCTD). She also had a massive proteinuria (3.2 g/day), and a kidney re-biopsy was performed (Figure 1). She was treated again with corticosteroid (prednisolone 20 mg daily) and her proteinuria had completely disappeared within a week.