Presence of a very large lobulated lower mediastinal soft tissue abnormality centered at the midline, which could represent a hiatus hernia; however, the lack of sufficient intraluminal gas precludes a definitive diagnosis. Differential considerations include a large lower esophageal mass or, less likely, an aneurysm, given the normal contour of the descending thoracic aorta.
Hernia (Uncertain) Inferior mediastinal mass (Uncertain)