Abstract
The relationship between an idiopathic deep vein thrombosis and a cancer is well established. It is not clear yet whether all patients with an idiopathic deep vein thrombosis should be thoroughly investigated for an occult cancer or only some. As a matter of fact, once a physician is faced with a patient who has an idiopathic deep vein thrombosis, three approaches are possible, mainly: 1) a wait and see approach; 2) a limited investigation; and 3) an extensive or invasive investigation. No sure criteria for the selection of the patients who should be extensively investigated are available. Suggestions have been made in this regard. Negative family or personal history for thrombosis, advanced age, deep vein thrombosis of upper limbs, existence of silent deep vein thrombosis in contralateral leg, tendency to relapse and/or to migrate, constitutional symptoms, or smoking may represent important clues that may justify an extensive study. This patient-oriented approach is mainly based on the experience of the caring physician.