Unusual cause of light chain cast nephropathy.

Acute kidney injury due to light chain cast nephropathy is increasingly recognised in patients with haematological malignancies; however, the management and prognosis of this disease remain poorly understood. We describe a case of a 78-year-old woman with known chronic lymphocytic leukaemia (CLL) who presented with fatigue and weight loss. She was found to have acute kidney injury, which rapidly worsened during admission. Kidney biopsy showed light chain cast nephropathy and bone marrow biopsy confirmed B-cell CLL. She was started on ibrutinib, halting further deterioration in her renal function and avoiding renal replacement therapy in the first 8 months.