Table 2. TNM staging by AJCC for appendiceal adenocarcinoma ^{11 50} .

Stage	T	N	M
X	Primary tumor not determined, or any T	Regional lymph nodes not determined, or any N	Metastatic disease not determined, or any M
0	No evidence of primary tumor	No regional lymph node metastasis	No distant metastasis
Is	Carcinoma in situ: intraepithelial or invasion of lamina propria	–	–
I	Tumor invades submucosa	Metastasis in 1–3 regional lymph nodes	Ia: Intraperitoneal metastasis beyond the right lower quadrant, including pseudomyxoma peritonei IIb: Nonperitoneal metastases
II	Tumor invades muscularis propria	Metastasis in four or more regional lymph nodes
III	Tumor invades through muscularis propria into subserosa or into mesoappendix
IV	IVa: Tumor penetrates visceral peritoneum, including mucinous peritoneal tumor within the right lower quadrant IVb: Tumor directly invades other organs or structures

Abbreviation: AJCC, American Joint Committee on Cancer.

Note : Stage I: T1–2 N0 M0; stage II: T3–4 N0 M0; stage III: Tx N1–2 M0; and stage IV: Tx Nx M1.