Maternal anatomical and physiological changes occur during pregnancy, particularly with cardiovascular and respiratory systems. Pregnant women with large mediastinal mass additionally have an increased risk of cardiopulmonary compromise. We report a 31-year-old patient at 30 weeks of gestation with a large anterior mediastinal tumour with superior vena cava obstruction. Her presenting symptom was progressive and severe dyspnea due to the large mediastinal mass. An ultrasound-guided biopsy was performed and the pathologic result was Hodgkin’s lymphoma. Termination of pregnancy and delivery of the neonate were performed using a Caesarean delivery under spinal anesthesia in the sitting position. The perioperative anaesthetic management was successful without any serious complications, and the postoperative outcomes were very impressive.