Masaoka stagingA system that is used clinically to stage thymomas, and is the most important determinant of survival post surgical resection; it is comprised of four stages (the last of which contains two sub-stages):
▪ Stage I—Intact thymic capsule;
▪ Stage II—Capsular invasion into adjacent mediastinal fat or pleura;
▪ Stage III—Macroscopic invasion into adjacent organs and vessels;
▪ Stage IVa—Dissemination in thoracic cavity (i.e pleural or pericardial implants); and
▪ Stage IVb—Distant metastases.
Stage II and above are regarded as thymic carcinoma.