TNM classification of malignant tumors 2010

In the 7th edition of the TNM classification most tumor entities have been left unchanged compared to the 6th edition, while some tumor entities and anatomical localizations have been newly introduced, thus following the basic principle of keeping classifications stable over time. In the 7th edition the categories "MX" and "pMX" have been eliminated because of misunderstandings and misuse. Only the categories "M0", "M1" and "pM1" are still valid and "pM0" is not to be used except after performing an autopsy. The classification of perineural invasion (Pn classification) has been newly established and its use is optional. The presence or absence of invasion of perineural spaces does not affect the T category but is considered an additional prognostic factor in some tumor entities.