Abstract
A 66-year-old man admitted for abdominal pain and vomiting was found in abdominal contrast-enhanced computed tomography to have a thrombus of the superior mesenteric vein and thickened small-intestine walls. Laboratory test showed low protein S activity and protein S antigen, leading to a diagnosis of superior mesenteric vein thrombosis caused by protein S deficiency. Anticoagulation therapy using heparin relieved symptoms, but one month later, he was referred for intestinal obstruction. When his condition failed to improve with conservative therapy, we conducted laparotomy, finding ileal stenosis 120 cm distal from the Treitz ligament and inflammatory adhesion around the stenotic ileum. We resected about 10 cm of the stenotic lesion with end-to-end anastomosis, then conducted anticoagulation and antiplatelet therapy using warfarin and aspirin. The postoperative course was uneventful. Superior mesenteric vein thrombosis caused by protein S deficiency is rare, with only 12 cases reported to our knowledge in Japan.
