Light Chain Deposition Disease and Light Chain Cast Nephropathy in a Patient With Multiple Myeloma and HIV Infection:...

Area of Science:

• Nephrology
• Hematology
• Infectious Diseases

Background:

• Kidney dysfunction is a frequent complication of multiple myeloma (MM).
• Light chain cast nephropathy is the typical renal biopsy finding in MM.
• Concurrent renal diseases are uncommon, especially in people living with human immunodeficiency virus (PLHIV).

Purpose of the Study:

• To report the first known case of concurrent light chain cast nephropathy and light chain deposition disease in a PLHIV with MM.
• To highlight the diagnostic utility of kidney biopsy in complex renal injury cases.

Main Methods:

• A case report of a male patient in his 50s with newly diagnosed HIV and community-acquired pneumonia.
• Clinical presentation of severe acute kidney injury requiring hemodialysis.
• Renal biopsy with histopathology, Congo red staining, electron microscopy, and immunofluorescence.

Main Results:

• Kidney biopsy revealed fractured, PAS-negative tubular casts with multinucleated giant cells.
• Electron microscopy showed granular subendothelial electron-dense deposits.
• Immunofluorescence confirmed lambda light chain restriction, leading to diagnoses of light chain deposition disease and light chain cast nephropathy.

Conclusions:

• This is the first reported case of concurrent light chain cast nephropathy and light chain deposition disease in a PLHIV with MM.
• Kidney biopsy is crucial for diagnosing acute kidney injury in PLHIV with concurrent myeloma.
• Early diagnosis and management are vital for improving renal outcomes.