Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
BACKGROUND: Trousseau's syndrome is a prothrombotic state associated with malignancy that is poorly understood pathophysiologically. METHODS AND RESULTS: Here we report studies on the blood of a 55-year-old man with giant-cell lung carcinoma who developed a severe form of Trousseau's syndrome. His clinical course was dominated by an extremely hypercoagulable state. Despite receiving potent antithrombotic therapy, he suffered eleven major arterial and venous thrombotic events over a 5 month period. We examined the patient's blood for tissue factor (TF), the major initiator of coagulation, and found its concentration in his plasma to be forty-one-fold higher than the mean concentration derived from testing of 16 normal individuals. CONCLUSION: Almost all of the TF in the patient's plasma was associated with cell-derived microvesicles, likely shed by the cancer cells.