The frontal & the lateral chest x-rays show a large posterior mediastinal mass with air-fluid level. The gastric air bubble is not visualized. These findings in the context of sudden epigastric pain should alert one to the possibility of a gastric volvulus.

The patient went on to have CT scans which confirmed the presence of gastric volvulus.

Gastric volvulus is a surgical emergency. It can cause acute gastric outlet obstruction as well as vascular compromise to the stomach. Classic presentation is with acute epigastric pain, dry retching, minimal vomiting and difficulty passing the nasogatsric tube. Predisposing factors are hiatus hernia, phrenic nerve palsy, diaphragmatic eventration, gastric distension and splenic abnormalities.

Reference: Grainger & Allison’s Diagnostic Radiology, A Textbook of Medical Imaging, 6th Edition.