Thymoma staging

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Amr Marawan, M.D. [2]

Overview

The thymic epithelial tumor staging system was initially proposed by Bergh and his colleagues in 1978,^[1] modified by Wilkins and Castleman in 1979,^[2] and further developed by Masaoka et al. in 1981.^[3]^[4]
Modified Masaoka staging grouped with TNM classification is the most widely adopted system for thymic epithelial tumors currently in use.

Modified Masaoka Clinical Staging of Thymoma

*Modified Masaoka Clinical Staging of Thymoma (1994)*^[5]
Stage	Description
I	Macroscopically and microscopically completely encapsulated
II	A. Microscopic transcapsular invasion B. Macroscopic invasion into surrounding fatty tissue or grossly adherent to but not through mediastinal pleura or pericardium
III	Macroscopic invasion into neighboring organs (ie, pericardium, great vessels, lung) A. Without invasion of great vessels B. With invasion of great vessels
IV	A. Pleural or pericardial dissemination B. Lymphogenous or hematogenous metastasis

TNM Classification of Thymic Epithelial Tumors

*TNM Classification of Thymic Epithelial Tumors by Yamakawa and Masaoka (1991)*^[6]
T/N/M Stage		Description
T factor	T1	Macroscopically completely encapsulated and microscopically no capsular invasion
	T2	Macroscopically adhesion or invasion into surrounding fatty tissue or mediastinal pleura, or microscopic invasion into capsule
	T3	Invasion into neighboring organs, such as pericardium, great vessels, and lung
	T4	Pleural or pericardial dissemination
N factor	N0	No lymph node metastasis
	N1	Metastasis to anterior mediastinal lymph nodes
	N2	Metastasis to intrathoracic lymphnodes except anterior mediastinal lymph nodes
	N3	Metastasis to extrathoracic lymphnodes
M factor	M0	No hematogenous metastasis
	M1	Hematogenous metastasis

*Combined Masaoka Staging/TNM Classification (1994)*^[7]
Masaoka Stage	T factor	N factor	M factor
Stage I	T1	N0	M0
Stage II	T2	N0	M0
Stage III	T3	N0	M0
Stage IVa	T4	N0	M0
Stage IVb	Any T	N1, N2, or N3	M0
Stage IVb	Any T	Any N	M1

Previously Reported Staging System

*Masaoka Staging (1981)*^[3]
Stage	Description
I	Macroscopically completely encapsulated and microscopically no capsular invasion
II	1. Macroscopic invasion into surrounding fatty tissue or mediastinal pleura 2. Microscopic invasion into capsule
III	Macroscopic invasion into neighboring organ (ie, pericardium, great vessels, or lung)
IVa	Pleural or pericardial dissemination
IVb	Lymphogenous or hematogenous metastasis

*Clinical Staging by Bergh (1978) and Wilkins (1979)*^[1]^[2]
Author	Stage	Description
Bergh et al.	I	Intact capsule or growth within the capsule
	II	Pericapsular growth into the mediastinal fat tissue
	III	Invasive growth into the surrounding organs and/or intrathoracic metastases
Wilkins et al.	I	Intact capsule or growth within the capsule
	II	Pericapsular growth into the mediastinal fat tissue or adjacent pleura or pericardium
	III	Invasive growth into the surrounding organs and/or intrathoracic metastases

References

↑ ^1.0 ^1.1 Bergh, NP.; Gatzinsky, P.; Larsson, S.; Lundin, P.; Ridell, B. (1978). “Tumors of the thymus and thymic region: I. Clinicopathological studies on thymomas”. Ann Thorac Surg. 25 (2): 91–8. PMID 626543. Unknown parameter |month= ignored (help)
↑ ^2.0 ^2.1 Wilkins, EW.; Castleman, B. (1979). “Thymoma: a continuing survey at the Massachusetts General Hospital”. Ann Thorac Surg. 28 (3): 252–6. PMID 485626. Unknown parameter |month= ignored (help)
↑ ^3.0 ^3.1 Masaoka, A.; Monden, Y.; Nakahara, K.; Tanioka, T. (1981). “Follow-up study of thymomas with special reference to their clinical stages”. Cancer. 48 (11): 2485–92. PMID 7296496. Unknown parameter |month= ignored (help)
↑ Kondo, K. (2005). “Invited commentary”. Ann Thorac Surg. 80 (6): 2000–1. doi:10.1016/j.athoracsur.2005.08.053. PMID 16305832. Unknown parameter |month= ignored (help)
↑ Masaoka, A.; Yamakawa, Y.; Niwa, H.; Fukai, I.; Saito, Y.; Tokudome, S.; Nakahara, K.; Fujii, Y. (1994). “Thymectomy and malignancy”. Eur J Cardiothorac Surg. 8 (5): 251–3. PMID 8043287.
↑ Sinha Hikim AP, Hoffer AP (1987). “Quantitative analysis of germ cells and Leydig cells in rat made infertile with gossypol”. Contraception. 35 (4): 395–408. PMID 3621939.
↑ Tsuchiya R, Koga K, Matsuno Y, Mukai K, Shimosato Y (1994). “Thymic carcinoma: proposal for pathological TNM and staging”. Pathol Int. 44 (7): 505–12. PMID 7921194.

Overview