Superior vena cava syndrome: the significance of endosonography in diagnosing enlarged mediastinal lymph nodes--a case report.

Superior vena cava syndrome is a rare, life-threatening clinical entity associated with occlusion of venous outflow from the head, neck and upper extremities. It is usually caused by an intrathoracic neoplasm, thrombosis, an aneurysm, or external compression. Benign diseases rarely cause this syndrome. Malignant neoplasms, including lymphoma, lung cancer and breast cancer frequently cause this syndrome. Herein, the case of a 63-year old patient who developed superior vena cava syndrome and dysphagia is reported. Endosonographic and CT investigation of the mediastinum confirmed enlarged lymph nodes exerting pressure on the superior vena cava and the esophagus, particularly at the level of the aortic arch. Cytologic examination of the lymph node specimen confirmed metastatic adenocarcinoma of the lung. The patient was treated by radiotherapy of the right lung and mediastinum. Patients with mediastinal tumors or enlarged lymph nodes frequently have dysphagic problems due to pressure on the esophagus. Endoscopy usually confirms a constriction of the lumen, but it cannot determine the cause. Endoscopic ultrasonography makes a precise differentiation between submucosal tumors and the causes of exterior compression possible.