To explore the causes of misdiagnoses and missed diagnoses of a case of partial anomalous pulmonary venous drainage (PAPVD) combined with atrial septal defect (ASD), in order to enhance the clinical awareness of the diagnosis of disease.

The clinical data, imaging findings, and surgical procedure of a patient with PAPVD and ASD, admitted to the Department of Cardiovascular Surgery at the Air Force Medical Center on July 28, 2025, were retrospectively reviewed. The literature was also consulted to identify key factors leading to diagnostic errors.

The patient was initially misdiagnosed as patent foramen ovale in another hospital. Although echocardiography at our institution correctly identified ASD, it failed to detect PAPVD. CT imaging mistakenly reported a persistent left superior vena cava. During ASD closure, an abnormal venous channel was discovered. Subsequent three-dimensional reconstruction of pulmonary artery computed tomography angiography confirmed anomalous drainage of the left superior pulmonary vein into the innominate vein. Postoperative supraclavicular ultrasound revealed the persistence of the abnormal drainage pathway.

PAPVD is prone to misdiagnosis and missed diagnosis, and is particularly likely to be overlooked when concomitant with ASD. Supraclavicular fossa echocardiographic views, combined with computed tomography and three-dimensional reconstruction, can improve diagnostic accuracy. Surgical strategy should be tailored based on multimodality imaging findings and patient-specific anatomic characteristics.