Mediastinal skip lymph node metastases in lung cancers and potential extrahilar communication of the lung to the mediastinum

We described the following contents to explain the existence of extrahilar direct communication of the upper pulmonary lobe to the mediastinum. 1. The specific patterns of mediastinal lymph node metastasis in N2 non-small cell lung cancers (NSCLCs), including skip N2 metastasis, which are associated with a favorable prognosis, 2. Pattern of lymphatic drainage to the mediastinum from each pulmonary lobes on the basis of CT observations of the primary complex of pulmonary histoplasmosis. 3. Septal structures between the pulmonary vein and the mediastinum on HRCT of normal subjects. 4. Bridging structures in the pleural space visualized on HRCT in the patients with pneumothorax. 5. Developmental process of pulmonary veins. The description would contribute to understand the specific LN involvement patterns with a favorable prognosis in NCSLCs.