A plasma cell disorder characterized by the aggregation and deposition of insoluble amyloid fibrils derived from misfolding of monoclonal immunoglobulin light chains usually produced by a plasma cell tumor. It usually presents as primary systemic amyloidosis (PSA) with multiple organ involvement and less frequently as primary localized amyloidosis (PLA) restricted to a single organ.

Multiple red/purple spots on the skin that surrounds the eyes that do not blanch (whiten) upon pressure. Purpura is caused by subcutaneous bleeding.