Tracheomediastinal fistula is a rare complication that occurs during the course of lung cancer. The fistula connects the airways to the mediastinum and is often associated with lymphoma. Clinical data on tracheomediastinal fistulas are limited to case reports. Tracheal stenting, pericardial and omental patch closure, and muscle flap closure can be performed to repair such fistulas. We herein report a case of tracheomediastinal fistula in a 47-year-old man.The main symptoms were shortness of breath and a feeling of fullness in the neck. Thoracic magnetic resonance imaging revealed an approximately 57 × 16 × 20 mm multiloculated cystic lesion with air density located in the upper mediastinum of the right paratracheal region and a fine fistula tract at this level. The main diagnosis was primary lung adenocarcinoma-related mediastinal lymphadenomegaly with a tracheomediastinal fistula.The patient underwent fistula opening on the trachea, which was then coagulated and sealed using argon plasma coagulation.The patient is currently asymptomatic and doing well 8 months after the intervention.