Intrathoracic caudate liver lobe with scimitar syndrome and aortic vascular ring.
Fifty-nine-year-old male referred to CT scan because of an anterior mediastinal mass incidentally detected at chest x-ray for check-up. Patient refers himself asymptomatic, cholecystectomy was performed 20 years ago and there is no history of traumatic abdominal or thoracic injury. Chest x-ray in PA view shows a subtle mass at right cardiophrenic angle, also visible at anterior mediastinum in lateral view. Non-contrast chest CT was performed initially, observing the caudate lobe of the liver passing through the diaphragmatic inferior vena cava hiatus into the right hemithorax with a stalk attaching it to the right lobe. Intravenous-contrast arterial and venous phases were added, extending scan to iliac crests. Intrathoracic caudate lobe was confirmed and a vascular shunt involving right inferior pulmonary artery and a pulmonary vein of the inferior lobe medial segment located anteriorly to the herniated caudate lobe and draining into the inferior vena cava located was detected, findings consistent with scimitar syndrome, there also was an abnormal arterial feeding segmental artery arising from the abdominal aorta, adjacent to the celiac trunk origin and ground-glass pattern of the involved lung segment. Left sided aortic arch with aberrant right subclavian artery was found and the right adrenal gland was ectopically located at the level of the IVC hiatus. The last incidental findings were two solid lung non-enhancing nodules (not-shown), one of them centrilobular, measuring 8 mm, rounded, with regular borders and a smaller subpleural nodule. Patient has already been scheduled for follow-up lung LDCT in three months. Heterotopic intra thoracic livers are an unusual finding. Twenty-four cases have been reported and none of them has been referred as associated with scimitar syndrome, heterotopic adrenal gland and left aortic arch with an aberrant right subclavian artery. The etiology is not well known, and is possibly due to proliferation of the liver bud in the thoracic cavity before the fusion of the diaphragmatic membranes. Only one case was associated with a vascular anomaly, an intralobar sequestration. Presence of scimitar syndrome in this case, besides the absence of traumatic history, supports the diagnosis of supradiaphragmatic liver. Figure 1. - Chest x-ray PA view. A subtle mass-like density is observed at the right cardiophrenic angle (arrow). Figure 2. - Chest x-ray lateral view. An anterior mediastinal mass with smooth borders is observed (arrow). Figure 3. - CT scan with IV-contrast, venous phase in axial plane showing the caudate lobe (asterisk) ascending into the right hemithorax through the inferior vena cava hiatus, esophagus is observed at its left side (arrow). Figure 4. - CT scan with IV-contrast, arterial phase demonstrates aberrant right subclavian artery (arrow) arising from the medial aspect of the distal aortic arch (asterisk). Figure 5. - CT scan with IV-contrast, arterial phase, volume rendering, which demonstrat