Heparin-like anticoagulant associated with plasma cell myeloma

A 54-year-old man with plasma cell myeloma had sustained bleeding develop after prophylactic hip hemiarthroplasty. Routine coagulation studies revealed significant prolongation of the prothrombin time, activated partial thromboplastin time, and thrombin time. Further evaluation showed failure of the activated partial thromboplastin time to correct in a 1:1 mixture with pooled normal plasma, correction of the prolonged thrombin time by addition of protamine, and a normal reptilase time. A purified preparation of the immunoglobulin component of patient plasma produced the same pattern of coagulation abnormalities, suggesting the paraprotein possessed heparin-like anticoagulant activity. This appears to be a rare mechanism of bleeding diathesis in plasma cell myeloma.