An atypical anti-GBM disease complicated by idiopathic nodular glomerulosclerosis: Case report

Both atypical anti-glomerular basement membrane (anti-GBM) disease and idiopathic nodular glomerulosclero-sis are rare diseases. We report a case of a 53-year-old non-diabetic male who present-ed with leg edema, nephritic range protein-uria, microscopic hematuria, and decreased renal function. The renal biopsy demon-strated membranoproliferative glomeru-lonephritis (MPGN) pattern of glomerular injury with focal crescent and segmental nodular glomerulosclerosis. The immuno-fluorescence studies showed intense linear IgG (IgG1 and IgG4) deposits along the GBM but negative serology. Electron microscopy demonstrated GBM thickening and fibril-lar deposition. The presence of MPGN with crescents and the linear IgG along the GBM were consistent with a diagnosis of atypical ant-GBM disease. Superimposed nodular glomerulosclerosis was considered to be id-iopathic by excluding other glomerular dis-eases characterized by fibrillar deposition and nodular glomerulosclerosis. Both dis-eases were found to have a strong causative association with patient's history of long-term heavy smoking. This unusual case with combination of atypical anti-GBM disease and idiopathic nodular glomerulosclerosis, has brought great challenge for the diagno-sis and also made the clinical course highly complicated. This nodular glomerulosclero-sis with anti-GBM-like glomerulonephritis may represent a distinct pattern of kidney injury observed in heavy smokers.