Anatomic basis of lymphatic spread from carcinoma of the lung to the mediastinum: surgical and prognostic implications.

Lymphatic spread of carcinoma of the lung to the mediastinum is an essential factor determining prognosis. An anatomic study of the mediastinal lymph nodes was made on 360 cadavers of adult subjects based on injection of the pulmonary segment. Eleven anatomic sites were involved. In 20 to 40% of cases the lymph reached these sites without any relay in the intrapulmonary lymph nodes. Within these sites the lymph flow continued towards the systemic circulation by traversing a variable number of lymph nodes, or sometimes none. The lymph flow reached the venous circulation in the neck, but in more than one case in ten the lymph had already entered the thoracic duct in the mediastinum, and in an intermediate number of cases the sites in the opposite mediastinum.