Table 4.

Clinical stage of thymic epithelial tumours according to Masaoka-Koga

Stage	Diagnostic criteria	10-yr survival
I	Tumours encapsulated macroscopically and microscopically (without capsular invasion)	84% (81%-86%)
II	A: Microscopic transcapsular invasion	83% (79%-87%)
	B: Macroscopic invasion of fatty tissue or pleural and/or pericardial adhesion
III	Macroscopic involvement of adjacent structures (pericardium, great vessels, or lung). A: With invasion of great vessels	70% (64%-75%)
	B: Without invasion of great vessels
IV	A: Pleural or pericardial spread	42% (26%-58%)
	B: Hematogenous or lymphogenic metastasis	53% (32%-73%)