Pseudo-obstruction of the interior vena cava in pediatric abdominal masses.

Extrinsic compression of the inferior vena cava by large abdominal masses may simulate occlusion on supine cavography. Seventeen children with large abdominal masses were evaluated by inferior venacavography. There was either occlusion or severe compression of the IVC on supine cavography in 13 patients; but the decubitus cavagram and subsequent surgery confirmed patency in 12 patients. In four patients only minor indentations or no abnormalities were present. Pseudo-obstruction of the IVC can be accurately differentiated from occlusion due to invasion by a lateral cavagram in the decubitus position.