BackgroundCongenital absence of the pericardium (CAP) is rare in clinical practice, the symptoms vary among patients, and most doctors do not have enough knowledge of the condition. Most reported CAP cases are incidental findings. Therefore, this case report aimed to present a rare case of left partial CAP that presented with non-specific, possibly cardiac-related symptoms.Case presentationThe patient, male, 56 years old, Asian, was admitted on March 2, 2021. The patient complained of occasional dizziness in the past week. The patient was suffering from hyperlipidemia and hypertension (stage 2), both untreated. The patient reported chest pain, palpitations, discomfort in the precordium, and dyspnea in the lateral recumbent position after strenuous activities, all of which started when he was about 15 years old. ECG showed sinus rhythm, 76 bpm, premature ventricular beats, incomplete right bundle branch block, and clockwise rotation of the electrical axis. Most of the ascending aorta could be detected in the parasternal intercostal space 2–4 by transthoracic echocardiography in the left lateral position. Chest computed tomography revealed the absence of pericardium between the aorta and the pulmonary artery, and part of the left lung was extending into the space. No changes in his condition have been reported up to now (March 2023).ConclusionsCAP should be considered when multiple examinations suggest heart rotation and a large moving range of the heart in the thoracic cavity.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12872-023-03262-3.