This patient had a large subdiaphragmatic hepatocellular carcinoma.

Causes of an elevated hemidiaphragm are:
1) Above the diaphragm – decreased lung volume (atelectasis, collapse, lobectomy, pneumonectomy, pulmonary hypoplasia).
2) Diaphragm – phrenic nerve palsy, diaphragmatic eventration
3) Below the diaphragm – abdominal tumour, subphrenic abscess, distended stomach or colon.

Differential diagnoses which may mimic an elevated hemidiaphragm are subpulmonic effusion, diaphragmatic hernia, diaphragmatic rupture and a tumour of the pleura or diaphragm.

Reference: Dahnert W. Radiology Review Manual, 5th edition. Lippincott, Williams and Wilkins 2003

Credit: Dr Donna D’Souza