Abstract: Hereditary hemorrhagic telangiectasia (HHT) caused by phosphatase and tensin homolog (PTEN) gene variation complicated with global cardiac enlargement is clinically rare. Herein, we report a case of a 27-year-old male patient with global cardiac enlargement. During a 7-year follow-up, the patient gradually developed chest distress, dyspnea and other symptoms. Imaging examinations showed progressive cardiomegaly, progressive pulmonary hypertension, aggravated tricuspid regurgitation with subsequent prolapse, and persistently elevated N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Pulmonary and hepatic artery CT angiography (CTA) revealed diffuse thickening of the pulmonary arteries, pulmonary veins and hepatic arteries, tortuous vascular shadows around the liver as well as in the thoracic and abdominal walls, accompanied by the presence of hepatic artery-portal vein/hepatic vein fistulas. Genetic testing indicated a suspected pathogenic variant, while no abnormalities were detected in the classic HHT-causing genes.