[Requiring Differential Diagnosis of Pulmonary Arteriovenous Fistula and Pulmonary Venous Aneurysm: Report of a Case].

A pulmonary arteriovenous fistula (PAVF) is a direct abnormal connection between the pulmonary artery and pulmonary vein, lacking capillary tissue. On the other hand, a pulmonary venous aneurysm (PVA) is a localized dilation and aneurysmal formation in the pulmonary vein without reflux issues. Treatment approaches for PAVF and PVA differ, considering surgery or catheter embolization for PAVF due to the risk of cerebral infarction or rupture caused by the abnormal shunt. PVA cases, being rare in rupture and embolism, are usually recommended for observation. Therefore, distinguishing between these two conditions is crucial. This article presents a case where both PVA and PAVF were present, necessitating a differential diagnosis.