A 68-year-old previously healthy man noticed swelling of his left leg after he had been playing golf. Two days after the onset of the symptom, he was admitted to our department with the diagnosis of deep venous thrombosis in his left leg. Decreased oxygenation and a mild CRP increase in laboratory data on admission. Since fibrinolytic and anticoagulant therapy with systemic administration of urokinase and heparin failed to reduce the local symptom, thrombectomy using a Fogarty balloon catheter was performed. On the 8th post-operative day, recurrence of deep venous thrombosis was detected by sonography. In addition, pulmonary embolism was detected by computed tomography following pulmonary angiography. A hereditary thrombotic background was suspected from the clinical feature of resistance to fibrinolytic and anticoagulant therapy and the complication of pulmonary embolism. The patient was found to be the heterozygote of familial deficiency of protein S. Protein S deficiency must be looked for in such a case in addition to AT-III deficiency and protein C deficiency, as an important hereditary thrombotic background.
