Fibrillary glomerulonephritis with prevalent IgA deposition associated with undifferentiated connective tissue disease: A case report.

We described a 41-year-old female patient, who presented with proteinuria occurring 5 years after the onset of an undifferentiated connective tissue disease (UCTD). At renal biopsy, a pattern of focal necrotizing glomerulonephritis with mesangial and parietal deposition of the IgA, C3 and K chains was observed. Electron microscopy showed organized fibrillary deposits in mesangial, subendothelial, intramembranous and subepithelial sites. Fibrils were randomly arranged, had no hollow core and had a diameter ranging between 10 and 23 nm. This case showed a rare combination of fibrillary glomerulonephritis and prevalent IgA deposition, in the clinical context of UCTD.