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Thymoma Staging System of Masaoka
|
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 |
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