engleski

C3 glomerulopathy – three case miniseries from pathohistological point of view

Background C3 glomerulopathy is a new entity characterized by the accumulation of C3 in the glomeruli, without significant deposition of the early components of the classical pathway complement activation, C1q and C4 and with minimal or no immunoglobulin deposition. Light microscopy (LM) morphology varies and includes mesangial proliferation, a membranoproliferative pattern, endocapillary proliferation and crescentic glomerulonephritis. There is C3 positivity on immunofluorescence (IF) analysis which corresponds to electron-dense deposits seen on electron microscopy (EM). Objective To present first three cases of C3 glomerulopathy diagnosed at Dubrava University Hospital. Methods and results First case was 39 year-old-woman diagnosed with C3 glomerulopathy on her third kidney biopsy. Patient presented with erythrocyturia and proteinuria. First two biopsies, performed in another institution, showed picture of focal, segmental, partially sclerosing and partially necrotizing glomerulonephritis with crescents on LM. For the first biopsy, there was weak C3 positivity on IF and EM performed in our institution as a consult was, at that time, interpreted as negative for immune deposits (later revision of biopsy showed few small deposits). Third biopsy was performed two years later at our institution and showed segmental scaring with adhesions, segmental endocapillary proliferation, hyaline thrombus and two small necroses. There was C3 2+ positivity only after repeated analysis with proteinase K specimen pre-treatment on IF. On EM dense deposit disease was seen. Second and third case were a 23 year-old-man with nephrotic syndrome and erithrocyturia and 53 year-old-woman with history of diabetes type II, microalbuminuria and without diabetic retinopathy. In both patients LM showed focal segmental sclerosing glomerulonephritis/glomerulopathy on LM, C3 2+ positivity on IF and deposits on EM. Conclusion C3 glomerulopathy is a rare entity with variable morphology on LM and we believe that our presentation of 3 cases will be beneficial for physicians facing diagnosing of this disorder.

C3 glomerulopathy; nephropathology

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