Abstract
A 65-year-old man was admitted to our hospital due to an abnormal shadow on chest radiographs. Chest computed tomography (CT) revealed a tumor (diameter: 38 mm × 27 mm) and another small nodule in the left upper lobe of the lung, which were accompanied by lymphangitis of the left upper lobe. The patient underwent a transbronchial lung biopsy, following which he was diagnosed with lung adenocarcinoma. Contrast-enhanced CT and ultrasound imaging revealed bilateral pulmonary artery thrombosis and multiple venous thromboses. He was thus diagnosed with stage IIB lung cancer complicated by Trousseau's syndrome. Chemotherapy was initiated using platinum doublets, while infusions of unfractionated heparin and Xa inhibitor were administered for anticoagulant therapy. Following chemotherapy, the main tumor had shrunk, and his lymphangitis, pulmonary artery thrombosis, and multiple venous thromboses had resolved. We then could perform a left upper lobectomy and lymph node dissection safely.