We discuss a fatal complication of percutaneous superior vena cava (SVC) self-expandable stent placement in a patient with superior vena cava syndrome (SVCS). The SVCS was caused by a malignant mediastinal mass with total occlusion of the SVC. Twenty-four hours after the procedure, the patient died of a hemopericardial tamponade. In the literature, only seven cases have been described with this life-threatening complication. Patients with a necrotic tumor mass are more likely to develop this complication. Knowledge of this complication may increase patient survival.