[Protein S deficiency and thrombophilia: presentation of a clinical case and review of the literature].

We report the case of a 22-year-old obese woman with severe protein S deficiency, probably genetic in nature, associated with recurrent venous thrombosis. Protein S deficiency is a rather rare disease: it may be an inherited, either homozygous (purpura fulminans at neonatal age), heterozygous, or acquired disorder. The thrombophilic state may be manifested as deep vein thrombosis or thrombophlebitis of the superficial veins with a high risk of pulmonary embolism in the young, and it is often exacerbated by pregnancy. In our case, the presenting event, bilateral deep venous (iliac-femoral) thrombosis complicated by disseminated intravascular coagulation, had occurred when the patient was 13 years old. We started long-term therapy with oral coagulants, i.e. warfarin even if the latter may cause skin necrosis ("warfarin dermatitis") in some patients with protein S deficiency. The clinician must consider protein S deficiency in cases of recurrent thrombosis, particularly in young patients: the importance of early implementation of long-term preventive therapy should not be underestimated.