I

Macro- and microscopically completely encapsulated tumour

II-A

Microscopic transcapsular invasion

II-B

Macroscopic invasion into surrounding fatty tissue or

grossly adherent

III

Macroscopic invasion into neighboring organs

III-A

Without invasion of great vessels

III-B

With invasion of great vessels

IV-A

Pleural or pericardial dissemination

IV-B

Lymphogenous or hematogenous metastases