This case report describes a rare and interesting case of a patient with multiple myeloma complicated with light chain (LC) cast nephropathy and focal amyloidosis. The patient presented with acute kidney injury, anaemia and bone lesions. The diagnosis was confirmed by bone marrow biopsy, serum and urine electrophoresis and kidney biopsy. The patient was treated with isazomil, pomalidomide and dexamethasone combination chemotherapy, followed by autologous stem cell transplantation. The patient achieved clinical remission, stable renal function and improved serum lambda free LC levels. This case highlights the challenges and advances in the diagnosis and treatment of this condition.