SUPERIOR VENA CAVA SYNDROME
Superior vena cava (SVC) syndrome is caused by extrinsic compression or internal thrombosis of the SVC, which compromises the venous drainage from the head and upper extremities. Lung cancer is responsible for the large majority of SVC syndrome in adults older than age 40 years. Lymphoma is the most common cause in younger individuals. Patients complain of a sensation of fullness in the head, cough, or dyspnea. They may experience lightheadedness, especially when bending over, or have edema and swelling in the head, neck, and arms. Edema of the larynx or pharynx may result in stridor, and cerebral edema may result in head-aches or confusion.
Physical ﬁndings include dilated neck veins and subcutaneous veins of the chest that persist with the patient in an upright position. Facial edema and a plethoric appearance may be present. Computed tomography chest scans with contrast injected through the arm veins show the mass with narrowing or obstruction of the SVC and the extensive venous collateral circulation of subcutaneous and mediastinal veins. If the SVC syndrome is caused by a benign condition such as ﬁbrosing mediastinitis, then a lung mass will not be identiﬁed.
Small cell carcinoma is the classic histology to cause SVC syndrome, but any histologic type may do so. Although SVC syndrome is a serious condition, it is not generally an emergency situation. Accordingly, a tissue diagnosis should be obtained before treatment begins. It is important to know if it is caused by lymphoma, small cell carcinoma, or non–small cell lung cancer before the appropriate treatment is instituted. SVC syndrome may occasionally be caused by other tumors (e.g., breast cancer, germ cell tumor), ﬁbrosing mediastinitis, or an infectious process (rarely). Bronchoscopy has a high diagnostic rate when SVC syndrome is caused by lung cancer. If bronchoscopy results are negative, then mediastinoscopy is the next logical procedure in most cases.
Treatment of patients with SVC syndrome should include stenting of the SVC early on in the process. This treatment quickly relieves the obstruction in more than 90% of cases. Chemotherapy alone as initial treatment is indicated for cases caused by small cell carcinoma or lymphoma, and radiotherapy or combined chemoradiotherapy is used for non–small cell lung cancer. Treatment should rarely be given without a tissue diagnosis. In patients with SVC syndrome caused by lung cancer, the long-term prognosis is related to the histologic type and stage of the disease at the time of initial diagnosis.