Lung adenocarcinoma with peculiar growth to the pulmonary artery and thrombus formation: report of a case

An 81-year-old woman was found to have an abnormal shadow on chest X-ray film. Computed tomography showed an irregularly bordered tumor centered in the hilar region extending from segment 6 to the middle lobe of the right lung. Pulmonary angiography showed complete occlusion of the trunk at the periphery proximal to the bifurcation of the posterior ascending branch. Based on bronchoscopic biopsy of the tumor, an adenocarcinoma was diagnosed. Middle and lower lobectomy was performed. Histopathologically, the adenocarcinoma had invaded the tunica intima of the pulmonary artery and also replaced the endothelium in the same region. Although a large thrombus was found at the vessel invasion site of the adenocarcinoma in the pulmonary artery, there were no malignant findings in the thrombus itself.This is the first reported case of radical resection of a lung cancer with invasion along the pulmonary artery wherein a benign thrombus had formed. In general, surgery would be the treatment of choice for a pulmonary artery mass.Tumors growing into the pulmonary arteries include angiosarcoma and tumor embolizations from other organs [1-5]. Despite being rare, there are several reports of primary lung cancers macroscopically growing into pulmonary arteries [6-8]. An intravascular tumor at the pulmonary artery represents a rare but important differential diagnosis of pulmonary thromboembolism [1,5,9]. Herein, we describe a patient with lung cancer that presented as a suspected pulmonary artery mass. The evaluation and treatment of this patient are presented in detail.An 81-year-old woman was found to have an abnormal shadow in the right lower lung field on chest radiography for a routine health check-up (Figure 1A). Her past medical history was unremarkable. Her smoking history was 1 pack/day × 50 years, and she had quit smoking at age 70. Chest computed tomography (CT) showed a tumor with an irregular border centered in the hilar region extending from segment 6 (S6) to the middl