Table 1 Stages of thymic tumors according to Masaoka-Koga classification and the proposed IASLC/ITMIG classification [5, 7, 13]
From: Evaluation of the new TNM-staging system for thymic malignancies: impact on indication and survival
Stage | Masaoka-Koga | IASCL/ITMIG |
|---|---|---|
I | Completely encapsulated tumor Invasion into but not through the capsule | T1N0M0 T1a: Encapsulated or extending into the anterior mediastinal fat T1b: Direct involvement of the mediastinal pleura |
II | (a) Microscopic transcapsular invasion (b) Macroscopic invasion into thymic or surrounding fatty tissue Grossly adherent to but not breaking through mediastinal pleura or pericardium | T2N0M0 T2: Invasion to the pericardium |
III | Invasion into neighboring organ including - Mediastinal pleura - Pericardium - Visceral pleura or lung - Phrenic or vagus nerve - Major vessels Adherence of lung or adjacent organs | (a) T3N0M0 T3: Invasion to - Lung - Brachiocephalic vein - Superior vena cava - Chest wall - Phrenic nerve (b) T4N0M0 T4: Invasion to - Aorta - Intrapericardial pulmonary artery - Myocardium - Trachea - Esophagus |
IV | (a) Pleural or pericardial metastases (b) Any nodal involvement and distant metastases | (a) TanyN1M0, TanyN0M1a N1: Anterior (perithymic) nodes M1a: Separate pleural or pericardial nodule (b) N2 and/or M1b N2: Deep intrathoracic or cervical nodes M1b: Pulmonary intraparenchymal nodule or distant organ metastasis |