Common renal involvements in patients with multiple myeloma are light chain cast nephropathy and AL amyloidosis. These entities usually show characteristic renal pathology by light microscopy. Rare patients show subtle renal histopathology which requires careful examination and high degree of suspicious from pathologists.
A myeloma patient showed mild proteinuria without renal impairment. By LM only subtle eosinophilic granules were detected in some endothelial cells of some glomeruli. Monoclonality was confirmed by IF to be IgG2/lambda. EM revealed accumulation of monoclonal immunoglobulin in lysosomes mainly in glomerular endothelial cells.
doi.org/10.1016/j.ekir.2019.09.012
