Feature	Thymoma	Thymic carcinoma
Organotypic (thymus‐like) histological features	Almost always present (lobular pattern, perivascular spaces, immature, TdT+/CD1a+/CD99+ T to cells)	None or abortive
CD5, CD70 and CD117 expression in epithelial cells	No	Frequent (~ 60%)
Invasion	Variable	Almost always
Myasthenia gravis	Variable: 10% to 80%	No
Other autoimmune diseases	Common	Rare
Clinical behaviour	Often curable by surgery; metastases are rare Usually long survival due to indolent clinical course	Often unresectable; metastases are frequent Often short survival due to progressive disease