Thymoma: does tumor size matter?

Prior to the American Joint Committee on Cancer (AJCC) 8^th edition, no AJCC or Union for International Cancer Control (UICC) stage classification system existed for thymic tumors. Historically, several staging systems have been used including the well-known Masaoka-Koga classification, which characterizes the anatomical extent of disease with respect to the tumor capsule and neighboring or distant structures (1).