Non-Secretory Myeloma, Diagnosed on Renal Biopsy as Cast Nephropathy

Abstract

Multiple myeloma is a disorder of plasma cells which can involve kidneys in the form of cast nephropathy. Neoplastic plasma cells produce either complete immunoglobulins or fragments of immunoglobulins leading to a monoclonal spike in the serum and/or Bence Jones proteinuria. Very few patients present as non-secretory myeloma when no immunoglobulins (M spike) are produced or only light chains are secreted which can only be detected in urine. Acute renal failure due to cast nephropathy can rarely be the first presentation of multiple myeloma. We here in report a case in which primary diagnosis of multiple myeloma was made on renal biopsy due to its characteristic histomorphology. The diagnosis was later on supported by presence of neoplastic plasma cells in the aspirate and biopsy of bone marrow.

Keywords: Fractured casts; Kidney biopsy; Plasma cell dyscrasia; Protein electrophoresis; Renal failure.

[Table/Fig-1]:

Dilated Renal tubules filled with pink eosinophilic fractured casts (H&E X400).

[Table/Fig-2]:

Giant cell reaction around casts with interstitium showing lympho-mononuclear infiltrate (PAS X400).

[Table/Fig-3]:

Tubules showing neutrophilic infiltrate around casts with reactive epithelium (H&E X400).

[Table/Fig-4]:

Serum protein electrophoresis curve without a peak in gama or beta region.

[Table/Fig-5]:

Bone marrow aspirate showing numerous plasma cells among other haematopoietic cells (MGG X400).