Masaoka's clinical stage[1] |
Stage I: Macroscopically completely encapsulated and microscopically no capsular invasion |
Stage II: Macroscopic invasion into surrounding fatty tissue or mediastinal pleura, or microscopic invasion into capsule |
Stage III: Macroscopic invasion into neighboring organs (ie, pericardium, great vessels, or lung) |
Stage IVa: Pleural or pericardial dissemination |
Stage IVb: Lymphogenous or hematogenous metastasis |
Koga's proposed pathologic tumor extent of thymic epithelial tumors[2] |
Stage I: Grossly and microscopically completely encapsulated |
Stage II: Microscopic transcapsular invasion or macroscopic invasion into thymic or surrounding fatty tissue, or grossly adherent to but not breaking through mediastinal pleura or pericardium |
Stage III: Macroscopic invasion of neighboring organ (eg, pericardium, great vessels, or lung) |
Stage IVa: Pleural or pericardial dissemination |
Stage IVb: Lymphogenous or hematogenous metastasis |
Yamakawa-Masaoka TNM classification and staging[3] |
T factor: |
T1: Macroscopically completely encapsulated and microscopically no capsular invasion |
T2: Macroscopically adhesion or invasion into surrounding fatty tissue or mediastinal pleura, or microscopic invasion into capsule |
T3: Invasion into neighboring organs, such as pericardium, great vessels, and lung |
T4: Pleural or pericardial dissemination |
N factor: |
N0: No lymph node metastasis |
N1: Metastasis to anterior mediastinal lymph nodes |
N2: Metastasis to intrathoracic lymph nodes except anterior mediastinal lymph nodes |
N3: Metastasis to extrathoracic lymph nodes |
M factor: |
M0: No hematogenous metastasis |
M1: Hematogenous metastasis |
Stage: |
Stage I | T1 | N0 | M0 |
Stage II | T2 | N0 | M0 |
Stage III | T3 | N0 | M0 |
Stage IVa | T4 | N0 | M0 |
Stage IVb | Any T | N1, 2, 3 | M0 |
Any T | Any N | M1 |