Rationale: This case describes the rapid resolution of acute airway obstruction after anesthesia induction in a young man with a massive 12.7 × 9 × 12 cm anterior mediastinal tumor. It emphasizes the remarkable effectiveness of positional adjustments in immediately alleviating airway compression caused by large mediastinal masses. The crisis was resolved quickly and without invasive measures through only positional tactics, without the need for emergency invasive interventions. This highlights the decisive role of strategic patient positioning as a primary technique for perioperative management of mediastinal masses, ensuring adequate ventilation and preventing catastrophic outcomes. Patient concerns: Due to the unique anatomical location of mediastinal tumors, the anesthesia risks for patients with mediastinal tumors are very high. These tumors can cause airway compression, leading to severe cardiovascular dysfunction and even mortality during general anesthesia. Diagnoses: Combining the patient’s medical history, symptoms and signs, fiberoptic bronchoscopy and excluding other causes, it was confirmed that the tumor compressed the airway and blocked the airway. Interventions: Ventilation was rapidly improved by adjusting the patient’s position, ultimately to the left lateral decubitus position with head-up tilt. Outcomes: Through positional adjustment, the patient’s airway obstruction symptoms rapidly improved. Airway pressure decreased significantly, end-tidal carbon dioxide returned to 40 mm Hg, and oxygen saturation increased to 95%. The mediastinal tumor was ultimately successfully resected. The surgical procedure went smoothly with successful extubation on the first postoperative day. The patient had a smooth recovery and was discharged on the seventh postoperative day without any lingering postoperative complications. Lessons: This case provides an important educational illustration of how mediastinal mass patients can develop sudden catastrophic airway obstruction after induction despite being asymptomatic preoperatively. It demonstrates an effective crisis rescue technique through positioning that may help inform management of similar high-risk cases.