Cross-sectional imaging in an inferior vena cava agenesis associated with antiphospholipid syndrome, lower limb, and portomesenteric deep vein thrombosis and renal insufficiency in a young patient: A rare presentation.

Inferior vena cava (IVC) agenesis is a rare congenital anomaly (prevalence 0.0005%-1%) often asymptomatic but can be complicated by deep vein thrombosis, particularly in the presence of acquired thrombophilia. There are 2 major presentations reported in literature, infrahepatic IVC agenesis associated mostly with lower-limb thrombosis and intrahepatic IVC agenesis associated frequently with splanchnic thrombosis and pulmonary embolism. We report the case of a 38-year-old man presenting with chronic bilateral leg ulcers evolving for 3 years. Cross-sectional imaging demonstrated partial agenesis of intra-hepatic IVC and complete agenesis of the infra-hepatic IVC up to the iliac bifurcation, a massive compensatory collateral network involving the azygos vein, hemiazygos, lumbar, and abdominal parietal systems, as well as multiple venous thrombosis of the portal vein, mesenteric vein, azygos vein and lower-limbs. The iliac veins drained via ascending lumbar veins to the hypertrophied azygos system. Morphology CT analysis showed a focal right renal infarct, but no atrophy was noted. Laboratory workup revealed a probable antiphospholipid syndrome (APS) and severe antithrombin III deficiency (22%), nephrotic syndrome, and alteration in glomerular filtration. This case illustrates the importance of recognizing radiological signs of IVC agenesis, particularly in the presence of atypical thrombosis or unexplained leg ulcers. The association with probable APS, multiple visceral thrombosis and renal function altered, makes this case exceptionally rare and educationally important.