A 57-year-old man with high alpha-fetoprotein (AFP) and suspected submucosal tumour of the stomach was referred for investigation. A 6 cm hypervascular tumour with tumour vessels in the left diaphragm was diagnosed by a combination of angiography and computed tomography. At laparotomy, the tumour was confirmed to be located just beneath the left diaphragm and to be isolated from the liver parenchyma. The resected specimen was histopathologically hepatocellular carcinoma. The level of AFP returned to normal, and the patient is free of recurrence 8 years after operation.