A condition characterized by an abnormally high level of thrombi. Causes include thrombotic thrombocytopenic purpura, disseminated intravascular coagulation, bone marrow disorders, and antiphospholipid antibody syndrome. A condition characterized by an abnormally high level of thrombi. Causes include thrombotic thrombocytopenic purpura, disseminated intravascular coagulation, bone marrow disorders, and antiphospholipid antibody syndrome. [ NCI ]