What is your diagnosis?           

 

  ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​

The photomicrograph shows a glomerulus on PAS stain with mesangial accumulation of homogenous PAS-pale material consistent with amyloid. This material showed positive staining by Congo Red with apple green birefringence on polarization (see below) and lambda light chain restriction on immunofluorescence (not shown) that is consistent with an AL-type, lambda light chain restricted renal amyloidosis.