Combined crystalline podocytopathy and tubulopathy associated with multiple myeloma.
Lymphoplasmacytic neoplasms cause a wide range of injuries to the kidney exemplified by light chain cast nephropathy and amyloidosis. Filtered paraproteins can also accumulate within kidney cells and cause direct cytotoxic injury. Rarely, paraproteins that are resistant to proteolysis can crystallize within proximal tubules and cause acute tubular injury. In contrast, accumulation of crystallized paraproteins in other kidney cells, especially podocytes, is exceptional. Here, we report the finding of crystalline inclusions within podocytes and proximal tubules in a patient who presented with a combined nephrotic syndrome and Fanconi syndrome. Further workup revealed previously unsuspected multiple myeloma and elevated serum free light chains, highlighting the protean presentation of paraprotein-mediated injuries to the kidney.
Department of Pathology, University of Washington, Seattle, WA 98195. Electronic address: shreeram@uw.edu.
Shreeram
S
Akilesh
Eastside Nephrology and Hypertension, PLLC, Kirkland, WA 98034.
Astier
A
Alem
Department of Pathology, University of Washington, Seattle, WA 98195; Pathology and Laboratory Medicine Services, Veterans Administration Puget Sound Health Care System, Seattle, WA 98108.
Roberto F
RF
Nicosia
D000818:Animals; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis; D002479:Inclusion Bodies / Q000648:ultrastructure*; D007674:Kidney Diseases / Q000209:etiology / Q000473:pathology*; D007687:Kidney Tubules, Proximal / Q000473:pathology*; D008297:Male; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009101:Multiple Myeloma / Q000150:complications / Q000473:pathology*; D050199:Podocytes / Q000473:pathology*
D007147:Immunoglobulin Light Chains
Collapsing glomerulopathy; Crystalline inclusions; Multiple myeloma; Podocyte