Abstract
Primary mediastinal large B-cell lymphoma (PMBCL) is a rare and potentially life-threatening tumor, especially when it causes compression of vital thoracic structures. Rapid diagnosis and timely treatment are essential, but diagnostic procedures may be complicated by severe airway obstruction. We report a case of a previously healthy 23-year-old female who presented with progressive orthopnea and facial edema over several weeks. Imaging revealed a massive anterior mediastinal tumor compressing the carina, main bronchi, and pulmonary arteries. A multidisciplinary team was involved early in the evaluation and discussed potential management strategies. Although initially stable, the patient developed shock on the second hospital day. Venoarterial extracorporeal membrane oxygenation (ECMO) was initiated to provide cardiopulmonary support and facilitate safe diagnostic intervention. Once hemodynamic and respiratory stability were achieved, endotracheal intubation and ultrasound-guided core needle biopsy (CNB) were performed. Anticoagulation was withheld until post-biopsy bleeding risk was ruled out. Rapid on-site evaluation suggested malignant lymphoma, and chemotherapy was initiated promptly. The tumor regressed rapidly, allowing for ECMO weaning on day nine. The patient was discharged without complications, and the final diagnosis established was PMBCL. We successfully provided prompt treatment for a large anterior mediastinal tumor causing respiratory and circulatory failure through a multidisciplinary approach, including ECMO support and rapid CNB diagnosis. Although this strategy may not be appropriate for tumors unresponsive to chemotherapy, it may be effective in cases of tumors likely to respond to chemotherapy, such as lymphoma. This report highlights the practical steps and clinical strategies that may guide the management of similar cases in emergency or critical care settings.