Fibrillary Glomerulonephritis: Clinicopathological Characteristics and Outcome-Case Series From a Multicentre Australasian Cohort.

Aim: Fibrillary glomerulonephritis (FGN) is a rare deposition disease with unclear aetiology. There are limited case series of FGN described in the literature. Here, we describe the clinicopathological characteristics and outcomes of a series of 26 patients with FGN diagnosed at an Australian tertiary centre for renal diseases over a decade.

Method(s): The present study includes 26 patients with biopsy-proven FGN diagnosed between January 2011 and December 2021.

Results: The average age at presentation was 60 years, with a female predominance. The mean creatinine at presentation was 205 μmol/L. Most of the patients had significant proteinuria, with an average 24-h urine protein of 3.76 g. Associated conditions included four patients with autoimmune disease, one patient with malignancy, and two patients with Hepatitis C infection. Serum electrophoresis demonstrated monoclonality in three patients, although immunofluorescence did not reveal clonal restriction on the renal biopsy. Most patients had mesangial expansion, with an increase in mesangial cellularity and variable degrees of capillary wall thickening. An established membranoproliferative pattern was seen in 10 patients. The median follow-up period was 33 months. Three patients received therapy targeted at FGN. End-stage kidney disease developed in 10 patients, with 6 patients dying during the follow-up period, mostly due to additional cardiovascular disease or sepsis.

Conclusion: This case series of FGN demonstrates that a significant proportion of patients progress towards end-stage kidney disease. The mortality is significant although the cause of death is due to additional conditions rather than directly due to FGN.