Cast Nephropathy: Clinicopathologic Analysis of 4 Cases

Multiple myeloma is a malignancy of plasma cells. Myeloma Cast Nephropathy (myeloma kidney), refers to intrinsic Acute Kidney Injury (AKI) that results as the filtered light chain component of M-protein (Bence-Jones protein) exerts toxic& obstructive injury to tubules. A total of 4 cases diagnosed with cast nephropathy between Jan2010-Apr2014 were analysed retrospectively as per histopathological and clinical criteria. All 4 cases were between age 44-62 yrs, 3 were males& 1 female.1 case showed light chain cast nephropathy with early features of acute tubulopathy. Second case showed evidence of light chain deposition disease with inflammatory tubulointerstitial nephritis alongwith light chain cast nephropathy. Rest 2 of the cases showed presence of cast nephropathy with superadded hypertension induced changes. Conclusion Cast nephropathy is seen in 30 to 50 % patients of multiple myeloma. The likelihood of underlying cast nephropathy is increased in cases of more profound AKI. Cast nephropathy can be misinterpreted as interstitial nephritis, amyloidosis, light chain deposition diseases, etc. , hence vital for nephrologists to review the histology with pathologists to avoid misdiagnosis.