A 59‑year‑old man presented to an emergency department with a 5‑year history of intermittent hemoptysis, which recurred following alcohol consumption 2 days ago. Computed tomography imaging demonstrated dilation of the artery in the upper lobe of the right lung, accompanied by ground‑glass opacity in the adjacent lung tissue (Figure 1A). Additionally, the right internal thoracic artery (ITA) was dilated, as compared with the left side (Figure 1B). Cinematic rendering image reconstructions showed the right anterior segment of the upper lobe of the lung extending to the anterior chest wall and establishing a connection with the right ITA (Figure 1C and 1D). A diagnosis of right ITA‑to‑right pulmonary artery fistula was confirmed. The patient underwent arterial embolization and remained stable during the subsequent 6 months of follow‑up.

A fistula between the ITA and the pulmonary vasculature (ITA‑to‑PV) represents a rare complication of coronary artery bypass grafting, typically affecting the left side.¹ To our knowledge, this is the first report of a right‑sided ITA‑to‑PV fistula. The abnormal blood flow near the fistula may lead to localized pressure changes in the pulmonary artery, creating local turbulence.² We hypothesize that repeated turbulence damaged the vascular endothelium, causing the vessel wall to degenerate and become fragile, particularly at the fistula site, thereby increasing the risk of bleeding and leading to hemoptysis.