A surgical case of pulmonary adenocarcinoma in the right upper lobe associated with a systemic artery-to-pulmonary artery fistula.

A 52-year-old female never-smoker with an abnormal shadow in the right lung detected on radiography was referred to our institution. Contrast-enhanced computed tomography revealed an irregular nodule in the upper lobe of the right lung, suggestive of a pulmonary vascular abnormality. Angiography revealed a direct communication between the right internal mammary artery (IMA) and the right upper lobe pulmonary artery branches, with dilated and tortuous vascular proliferation. As multiple branch arteries were seen flowing into the upper lobe from the IMA, transcatheter selective embolization of these vessels and right upper lobectomy by video-assisted thoracoscopic surgery were performed. Contrary to the clinical diagnosis, the pathological finding was a pulmonary adenocarcinoma of the right upper lobe. Additional lymph node dissection was performed later. We report an extremely rare and unprecedented case of pulmonary adenocarcinoma fed by the right IMA, with a literature review.