Collapsing Glomerulopathy in Lambda Light Chain Amyloidosis: A Report of 2 Cases

Area of Science:

• Nephrology
• Pathology
• Oncology

Background:

• Amyloid nephropathy is an uncommon kidney disease typically presenting with reduced function and proteinuria, often associated with paraproteinemia in developed countries.
• Histologically, glomerular amyloid deposition involves mesangial and capillary wall infiltration by amorphous material, usually without endo- or extracapillary proliferation.
• While rare crescentic injuries are reported, collapsing glomerulopathy has not been previously associated with amyloid nephropathy.

Observation:

• This report describes two patients with acute kidney injury and nephrotic syndrome.
• Kidney biopsies revealed amyloid nephropathy characterized by prominent epithelial cell hyperplasia and glomerular collapse.
• This presentation is distinct from typical amyloid nephropathy histology.

Findings:

• The study identifies a novel association between amyloid nephropathy and collapsing glomerulopathy.
• The observed glomerular collapse and epithelial hyperplasia suggest a complex injury pattern.
• This finding expands the known renal manifestations of paraprotein-associated kidney disease.

Implications:

• The findings broaden the understanding of the spectrum of renal injury in paraproteinemia.
• This highlights the importance of considering collapsing glomerulopathy in amyloid nephropathy patients with acute kidney injury.
• Further research into the pathomechanisms of podocyte injury and vascular compromise in this context is warranted.