Recurrent deep vein thrombosis and pulmonary embolism in a patient with Klinefelter's syndrome.

Klinefelter's syndrome, which is characterized by small testes, gynecomastia, hypogonadism, and infertility, is the most common cause of primary testicular failure, and commonly has an XXY karyotype. Deep vein thrombosis and thomboembolic events are a rare occurrence in these patients. Although the exact mechanism is not completely understood, it is thought that increased thromboembolic risk in hypogonadic men can be explained by hypofibrinolysis resulting from androgen deficiency. We present the case of a 48-year-old man with Klinefelter's syndrome who experienced recurrent episodes of deep venous thrombosis and pulmonary embolism while undergoing therapeutic anticoagulation. Our report discusses this association and management of the prothrombotic state in patients with Klinefelter's syndrome.