Unusual Fibrillary Glomerulonephritis in a 19-Month-Old Male Patient: A Case Report and Review of the Literature

Fibrillary glomerulonephritis (FG) is an immune-mediated type of glomerulonephritis characterized by Congo red-negative fibrillary electron-dense deposits. The incidence of FG is less than 1% in adults and it is very rare in children. We herein present a case of FG in a child with steroid-resistant nephrotic syndrome (SRNS). Nephrotic syndrome was diagnosed in a 19-month-old male patient based on the presence of periorbital edema and nephrotic-range proteinuria. Renal biopsy was performed because of the lack of response to eight weeks of prednisolone treatment and FG was diagnosed by electron microscopy. Unusual IgM deposits were present on immunofluorescence microscopy, contrary to previousreportsin the literature. Because steroids and cytotoxic drugs were ineffective for the treatment of FG, an angiotensin-converting enzyme inhibitor (ACEi) was started. Monotherapy with the ACEi, caused the proteinuria to fall from the nephrotic-range to the subnephrotic-range. This case illustrates that although very rare in childhood, FG should be considered as a differential diagnosis of SRNS. Additionally, the prognosis of FG childhood is much better than that of FG in adulthood. ACEi therapy alone may be considered in the treatment of FG in childhood.