Background: Significant capillary proliferation is common in post-streptococcal acute
glomerulonephritis (PSAGN) after streptococci and is a prognostic disease. Focal
segmental glomerulosclerosis is a disease characterized by segmental sclerosis although it
may have a poor prognosis
Case Presentation: A 50-year-old man with nephrotic syndrome underwent renal biopsy,
which showed marked endocapillary proliferation due to enlarged vascular endothelial
cells and infiltration of lymphocytes. However, there was no mesangial cell proliferation,
mesangial matrix increase, or crescent formation. Electron microscopy showed fusion of
podocytes without any electron-dense deposits. Immunostaining for CD68 and CD3 was
positive, and the presence of macrophages and T-cells was suggested. Steroid therapy,
including pulse therapy, was performed, and then cyclosporine was added to steroid
therapy. Although urinary protein decreased, his renal function did not respond well to
steroid therapy, and the patient initiated dialysis 2 years later.
Conclusions: We report this case considering that it was nephritis of unknown origin
showing segmental endocapillary proliferation that had not been recognized previously.