Deep venous thrombosis in the presence of congenital hypoplasia of the inferior vena cava

We report a case of hypoplasia of the inferior vena cava (IVC) presenting with deep venous thrombosis of the left lower limb. Duplex scanning, ascending venography and inferior cavography demonstrated thrombosis up to the left iliac axis without satisfactory IVC images; collateral venous circles were evident. Thrombosis extending into the IVC was suspected but computed tomography scan revealed hypoplasia of the IVC with a filiform vein ascending to the retrohepatic level, dilated and tortuous collateral venous circles, parallel to the IVC, and dilated azygos and hemiazygos veins. Congenital anomalies of the IVC are: uncommon events, generally asymptomatic, and no individual surgeon or radiologist acquires a wide experience. Developmental interruption of the IVC with azygos and hemiazygos continuation is one of the most common anomalies; in our patient, the infrarenal IVC was not absent but underdeveloped, and the azygos and hemiazygos veins, although dilated, did not continue it