Transesophageal echocardiography (TEE) has become a mainstay of cardiac surgery in the diagnosis of intracardiac and vascular lesions adjacent to the esophagus. In this case, we detected a liver mass during intraoperative TEE examination in a patient undergoing elective cardiac valve surgery. Preoperatively, the patient had normal liver function tests and no symptoms of hepatocellular carcinoma. This mass was diagnosed as hepatocellular carcinoma after the surgery and treated with transarterial chemoembolization. In conclusion, this case report outlines another potential application of intraoperative TEE extending its role outside the realm of cardiac surgery.