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.

An embolus (that is, an abnormal particle circulating in the blood) located in the pulmonary artery and thereby blocking blood circulation to the lung. Usually the embolus is a blood clot that has developed in an extremity (for instance, a deep venous thrombosis), detached, and traveled through the circulation before becoming trapped in the pulmonary artery.