Systemic light chain deposition disease presenting as multiple pulmonary nodules. A case report and review of the literature.

This case report describes the primary manifestation of systemic light chain deposition disease as bilateral nodules on chest radiographs. Although this case was initially classified as amyloidosis, a subsequent renal biopsy and ultrastructural, histochemical, and immunohistochemical studies allowed its distinction from amyloidosis. Kappa light chains were expressed with immunoperoxidase studies on paraffin-embedded tissue, and ultrastructural studies showed the dense, granular deposits characteristic of systemic light chain deposition disease. Serum and urine electrophoresis showed a monoclonal spike, but no plasmacytosis was identified at bone marrow biopsy and autopsy. The literature on this subject is also herein reviewed, with particular attention to the extrarenal manifestations of systemic light chain deposition disease.