Diagnose This! (November 6, 2017)

What is your diagnosis?

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The electron photomicrograph shows microtubular structures arranged in parallel arrays that is typical of immunotactoid glomerulopathy. Immunotactoid glomerulopathy frequently shows IgG staining by immunofluorescence that is often light chain restricted and should be Congo red negative (both present in this case but not shown). Currently, the etiology of immunotactoid glomerulopathy is unclear and there is controversy involving whether these findings represent a discrete disease process or whether this entity represents just an unusual organization pattern of immunoglobulins in other diseases (such as paraprotein-associated glomerulonephritis).