Appendix (ICD10 C18.1)

This is the data sheet for TNM 9th edition staging of the appendix (ICD10 C18.1).

For more detailed information regarding TNM staging, please see pages 72-74 of the UICC TNM 9 book.

T - primary tumour

Note

^aThe Tis(LAMN) category does not apply HAMNs; HAMN are staged using the appendiceal adenocarcinoma T categories

^bT1 and T2 are not applicable to LAMN; acellular mucin or mucinous epithelium that extends into the subserosa or serosa should be classified as T3 or T4a, respectively 

^cDirect invasion in T4 includes invasion of other intestinal segments by way of the serosa, e.g. invasion of ileum. Tumour that is adherent to other organs or structures, macroscopically, is classified as cT4b. However, if no tumour is present in the adhesion, microscopically, the classification should be pT1, 2 or 3

N - regional lymph nodes

Note

* Tumour deposits (TDs) represent discrete tumour nodules of any shape, contour or size in peri-rectal and peri-colonic fat, away from the leading edge of the tumour, within the lymph drainage area of the primary carcinoma. TDs can originate from different histological structures, including lymph nodes, vessels and nerves. Therefore, TDs may contain foci of extramural vascular invasion (EMVI) and perineural invasion (PNI). The feature distinguishing a TD from EMVI and PNI is the presence of unequivocal tumour extension from the vessel or nerve into the surrounding fat or fibroconnective tissue. When tumour outgrowth from EMVI and/or PNI is present, the diagnosis of TDs and EMVI/PNI should be denoted separately in the report. If the tumour involves an identifiable lymph node, it is considered as lymph node metastasis and not as TDs even if the tumour extends into the perinodal fat.

M - distant metastasis

pT - primary tumour

The pT and pN categories correspond to the cT and cN categories as per above.

pN - regional lymph nodes