Table 5.

Clinical stage of thymic epithelial tumours: International Association for the Study of Lung Cancer/International Thymic Malignancy Interest Group tumor-node-metastasis

Stage		Description
Primary tumor (T)
T1	T1a	Encapsulated or unencapsulated, with or without extension into mediastinal fat
	T1b	Extension into mediastinal pleura
T2		Direct invasion of the pericardium (partial or full thickness)
T3		Direct invasion of the lung, brachiocephalic vein, superior vena cava, chest wall, phrenic nerveand/or hilar (extrapericardial) pulmonary vessels
T4		Direct invasion of the aorta, main pulmonary artery, myocardium, trachea, or esophagus
Lymph nodes (N)
N0		No nodal involvement
N1		Anterior (perithymic) lymph nodes (IASLC levels 1, 3a, 6 and/or supradiaphragmatic/inferior phrenic/pericardial)
N2		Deep cervical or intrathoracic nodes (IASLC levels 2, 4, 5, 7, 10 and/or internal mammary nodes)
Distant metastasis (M)
M0		No pleural, pericardial, or distant metastases
M1	M1a	Pleural or pericardial nodules
	M1b	Pulmonary intraparenchymal nodule or distant organ metastasis
TNM stage		MASOKA-KOGA stage
I	T1N0M0	I, IIA, IIB, III
II	T2N0M0	III
IIIA	T3N0M0	III
IIIB	T4N0M0	III
IVA	Any T, N0-1, M0-1a	IVA, IVB
IVB	Any T, N0-2, M0-1b	IVB

IASLC: International Association for the Study of Lung Cancer; TNM: Tumor-node-metastasis.