Mesenteric-portal axis thrombosis and deep venous thrombosis in a patient with inferior vena cava agenesis.

Splenoportal axis thrombosis not associated with cirrhosis or neoplasms has a prevalence lower than 5 per 10,000 people. An etiologic factor responsible for portal thrombosis is finally identified in most cases, usually systemic thrombogenic factors or predisposing local factors. However, despite a detailed study of all etiologic factors, up to 30% of cases are eventually considered as idiopathic in origin. We report the case of a 41-year-old patient who presented with abdominal pain and lower extremity edema. The patient was diagnosed with portal and mesenteric-portal confluence thrombosis, bilateral deep venous thrombosis and right lumbar vein thrombosis based on an abdominal CT scan. This was associated with a likely congenital inferior vena cava agenesis. This malformation is present in approximately 5% of patients with deep vein thrombosis even though it represents a rare cause of portal thrombosis. The fact that several thromboses developed simultaneously makes this a unique and isolated case in the current literature as no similar cases have been reported thus far.