Fibrillary noncongophilic renal and extrarenal deposits: A report on 10 cases

Cases in which glomerular deposits of Congo red negative amyloid-like fibrils were demonstrated by electron microscopic identification are included in this study. In the 1,266 kidney biopsies studied, there were 9 biopsies from 8 patients with fibrillary glomerulonephritis and 2 biopsies from 2 patients with systemic lupus. In 1 case of fibrillary glomerulonephritis (FGN), autopsy was performed. Electron microscopic examination showed glomerular (100%) and extraglomerular (60%) fibrillary deposits in the biopsy samples of patients with FGN and also in patients with systemic lupus. In the autopsy case, similar fibrillary deposits were demonstrated in the kidney, pancreas, spleen, lungs, and liver. The diameter of the fibrils, which were arranged similarly in all cases, varied from 8 to 27 nm individually, the length being about 1.5 mum. The authors speculate that extraglomerular kidney fibrillary deposits concurrent with the same type of deposits in other organs suggests systemic manifestation of FGN.