The excretion of light chains causes tubular damage, generating obstructive nephropathy known as "myeloma kidney." This nephropathy is characterized by three main components: proximal renal tubular atrophy, the formation of eosinophilic cylinders in the distal tubule, and inflammation with interstitial fibrosis [5]. The typical histopathological finding is the presence of light chain eosinophilic cylinders inside the lumen of the renal tubules surrounded by cells - multinucleated giants generating a "foreign body" reaction in the distal tubules and collecting duct (Figure 6).