Infrarenal inferior vena cava agenesis and recurrent deep vein thrombosis: a case report and literature review.

Inferior vena cava agenesis is a rare congenital vascular defect often diagnosed as an incidental finding in asymptomatic patients. When symptoms arise, it can present with chronic venous stasis or unprovoked deep vein thrombosis (DVT). A 42-year-old man with history of unprovoked right lower extremity (RLE) DVTs was admitted for swelling, pain and erythema to the RLE, concerning for new DVT. Venous Doppler ultrasound showed a chronic DVT of the right proximal femoral vein in addition to an acute DVT of the distal femoral vein. Extensive thrombophilia workup was negative and additional imaging with abdominal computed tomography scan revealed the absence of the infrarenal inferior vena cava. Patient was treated with oral anticoagulation and compression stockings and discharged with clinical improvement. At 3-month follow-up, patient was completely asymptomatic. Recurrent unprovoked DVTs in young patients require exhaustive work up including imaging studies to rule out vascular anomalies.