AL amyloidosis

**Definition:** AL (Amyloid Light-Chain) Amyloidosis is due to the deposition of immunoglobulin light chains in glomeruli where they are seen as Congo red binding fibrils and immuno-stain specifically for kappa or lambda light chains. By light microscopy there is amorphous hyaline material in the mesangium and capillary walls. A light chain producing plasma cell or B-cell dysplasia is responsible. Other organs are also involved in this systemic disease.