Trousseau was the first who describe an association of venous thromboembolism (VTE) with malignancy. The prevalence of occult cancer in patients with secondary VTE is comparable with the prevalence of cancer in general population (2 - 3 %), while the prevalence of occult cancer in patients with idiopathic VTE is 4 - 10 %. It has been demonstrated that the frequency of malignancy is higher in the first 6 to 12 months after diagnosis of VTE. 113 consecutive patients (50 males, 63 females) with first or recurrent VTE before the age 50, mean age (mean age 34.1 at time of VTE diagnosis) were followed retrospectively. Patients with known cancer were excluded for followup. The presence of known malignancy and concomitant cancer at the time of diagnosis of VTE and during follow-up (average 29 months) was investigated. The use of routine or extensive screening detection of occult cancer was also assessed. Extensive screening was performed in 61 % of patients and compared with 39 % of routine screening. Overall of occult cancer was 1.8 %. The incidence of occult cancer was 1.2 % during one year follow-up, and the prevalence at the time of diagnosis of VTE was 0.9 %. The authors confirmed the low prevalence of occult cancer in cohort of consecutive young patients with VTE under the age of 50. It seems that only routine investigation with careful history taking, physical examination and simple laboratory tests are sufficient to detect of occult cancer in this age population. The authors recommend the follow-up of these patients, mainly those with idiopathic VTE. Inherited thrombophilia much more prevails in this young thrombophilia patients but risk of occult malignancy exists as well.

        Key words: Venous thromboembolism - Young patients - Occult cancer - Routine and extensive screening