The most current map of intrathoracic lymph nodes is the International Association for the Study of Lung Cancer (IASLC) map. Stations 1–9 correspond to mediastinal nodal groups, while stations 10–14 represent hilar and other more peripheral extra mediastinal nodal groups. In contrast to the functional subdivisions, intrathoracic LN locations have been traditionally mapped into 14 stations according to their relationship to landmarks encountered during mediastinoscopy and thoracotomy for lung cancer. Dividing the mediastinum helps to narrow down the lengthy differential diagnoses, which can present in the thorax (including, but not limited to: infections like tuberculosis, the nodal spread of lung cancer, sarcoidosis, lymphoma, silicosis, and asbestosis). Lymph nodes (LNs) are present in all three functional compartments of the mediastinum, though most lymphatic tissue is found in the anterior and middle compartments, and the etiology of lymphatic pathology varies by subdivision. These subdivisions are used to describe the locations of lesions, thereby helping to facilitate differential diagnoses and communication between providers. The mediastinum is classically subdivided into three functional divisions: anterior (pre-vascular), middle (visceral), and posterior (paravertebral) mediastinum. The mediastinal compartment contains multiple critical organs and vessels and serves as the central hub for lymphatic drainage.

Shotty metastatic lymph nodes