The superior vena cava (SVC) syndrome occurs when obstruction of this vessel interrupts venous return of blood from the head, upper extremities and thorax to the right atrium. Most cases of SVC syndrome result from neoplasia, especially from lung cancer, but other non-cancer-associated causes may include fibrosis caused by radiotherapy, collagen-vascular diseases, arteriovenous shunts or thrombosis as a complication of use of central venous catheters or devices. We report here the case of a 60-year-old woman with non-small cell lung cancer who was treated, after three lines of chemotherapy, with the epidermal growth factor receptor inhibitor erlotinib and subsequently presented to the hospital with abrupt onset of syncope, shortness of breath and cyanosis (face, neck and trunk). A CT scan of the chest demonstrated a massive thrombosis of both brachiocephalic veins and the SVC. The patient was treated with the systemic thrombolytic agent urokinase, with resolution of the clinical picture and no bleeding complications. The possible pathogenetic causes of thrombosis of the brachiocephalic veins and SVC syndrome in this case are discussed. It is possible that acute thrombosis may be associated with erlotinib use, even if it is likely that cancer may be the main cause of the thrombotic complication.