Stage	Description
I	Macroscopically, completely encapsulated; microscopically, no capsular invasion
II	Macroscopic invasion into surrounding fatty tissue or mediastinal pleura; microscopic invasion into capsule
III	Macroscopic invasion into neighboring organs (pericardium, lung, and great vessels)
IVa	Pleural or pericardial dissemination
IVb	Lymphogenous or hematogenous metastases