Fibrillary glomerulonephritis in a 9-year-old girl.

A 9-year-old girl presented with mild proteinuria and microscopic hematuria. Renal biopsy disclosed highly organized fibrillary deposits in glomerular mesangial areas by ultrastructural examination. The microfibrils were 10-15 nm in diameter, up to 1,200 nm in length and in parallel array. They did not have a microtubular appearance. The diameter of the microfibrils was larger than that of amyloid fibrils. Congo red and crystal violet stains were negative. There was no clinical or serologic evidence of paraproteinemia, cryoglobulinemia, light chain disease or systemic lupus erythematosus. To date, most of the reported cases of fibrillary glomerulonephritis have occurred in adults; this disorder is extremely rare in children. We believe that this glomerulopathy can occur in the pediatric age group and should be considered in renal biopsy diagnoses.