Superior vena caval syndrome is most commonly caused by:
a. Central or endobronchial growth of the primary tumor may cause cough, hemoptysis, wheeze and stridor, dyspnea, and postobstructive pneumonitis (fever and productive cough).
b. Peripheral growth of the primary tumor may cause pain from pleural or chest wall involvement, dyspnea on a restrictive basis, and symptoms of lung abscess resulting from tumor cavitation.
c. Regional spread of tumor in the thorax (by contiguous growth or by metastasis to regional lymph nodes) may cause tracheal obstruction, esophageal compression with dysphagia, recurrent laryngeal nerve paralysis with hoarseness, phrenic nerve paralysis with elevation of the hemidiaphragm and dyspnea, and sympathetic nerve paralysis with Horner's syndrome (enophthalmos, ptosis, miosis, and ipsilateral loss of sweating). Malignant pleural effusion often leads to dyspnea.
d. Pancoast's (or superior sulcus tumor) syndrome results from local extension of a tumor growing in the apex of the lung with involvement of the eighth cervical and first and second thoracic nerves, with shoulder pain that characteristically radiates in the ulnar distribution of the arm, often with radiologic destruction of the first and second ribs.
e. Often Horner's syndrome and Pancoast's syndrome coexist.
f. Other problems of regional spread include superior vena cava syndrome from vascular obstruction; pericardial and cardiac extension with resultant tamponade, arrhythmia, or cardiac failure; lymphatic obstruction with resultant pleural effusion; and lymphangitic spread through the lungs with hypoxemia and dyspnea.