A Rare Case of Persistent Left Upper Lobe Non-expansion After Resection of a Giant Mediastinal Mature Teratoma Managed With Lobectomy

Giant mediastinal mature teratomas can compress the lungs, airways, and great vessels, although lung reexpansion after tumor removal is not always achieved.A 60-year-old woman with a history of childhood poliomyelitis presented with progressive dyspnea and weakness over 12 days, followed by gasping respiration and decreased consciousness requiring intubation and mechanical ventilation.Admission arterial blood gas analysis showed severe hypercapnic respiratory failure with acidemia (pH 7.258, partial pressure of carbon dioxide (PaCO₂) 87.9 mmHg).Computed tomography revealed a 15.76-cm anterior mediastinal mass containing fat and calcification, displacing the heart and great vessels, narrowing the right pulmonary artery, and causing compressive atelectasis of the left lung.Bilateral pulmonary opacities, right lower lobe bronchiectasis, and a sputum culture positive for Pseudomonas aeruginosa suggested possible concomitant pulmonary disease.The well-circumscribed tumor was resected through a left hemiclamshell incision with median sternotomy, with no gross evidence of invasion into adjacent structures.Despite intraoperative re-expansion attempts, the left upper lobe remained collapsed, and left upper lobectomy was performed.Histopathology confirmed a mature teratoma, while examination of the resected lobe showed atelectasis without tumor involvement.The patient remained ventilator-dependent after an unsuccessful extubation attempt and later developed severe metabolic and hemodynamic deterioration, including hypoglycemia and refractory hypotension despite maximal vasopressor support.The patient died on postoperative day 8 after further clinical deterioration.This case demonstrates that the left upper lobe may fail to re-expand despite removal of a compressing mediastinal mass and intraoperative re-expansion attempts, even in the absence of tumor involvement on histopathology.