Abstract

Thirty-seven percutaneous renal biopsies showing no significant abnormalities on light microscopy were studied electron optically and by immunofluorescence when available. Assessment of the pathological material was followed by analysis of the patients' clinical notes, and a clinicopathological correlation was carried out. Twenty-three patients fulfilled the clinical criteria of minimal change disease; 10 did not behave clinically as minimal change and showed immune complex deposition; two had benign recurrent haematuria; and two had myelomatosis. Our study shows that if diagnosis is based solely on the light microscope appearances of renal biopsy, diseases other than minimal change are likely to be overlooked. Accuracy of diagnosis in structural terms requires additional immunofluorescence and electron microscopic study; final clinical diagnosis also requires careful follow-up, and repeat biopsy may be necessary.