Management of incidentally discovered appendiceal neuroendocrine tumors after an appendicectomy

Table 1 TNM staging for appendiceal neuroendocrine tumor according to European Neuroendocrine Tumor Society and American Joint Committee on Cancer classification

	ENETS	AJCC
T0	No evidence of primary tumor	No evidence of primary tumor
T1	Tumor ≤ 1 cm with infiltration of submucosa and muscularis propia
T1a		Tumor ≤ 1 cm
T1b		Tumor 1-2 cm
T2	Tumor ≤ 2 cm with infiltration of the submucosa, muscularis propia and/or minimal (≤ 3 mm) infiltration of the subserosa and/or mesoappendix	Tumor 2-4 cm or with extension into the cecum
T3	Tumor > 2 cm and/or extensive (> 3 mm) infiltration of the subserosa and/or mesoappendix	Tumor > 4 cm or with extension into the ileum
T4	Tumor with infiltration of the peritoneum and/or other neighboring organs	Tumor with perforation of the peritoneum or invasion of other adjacent structures
N0	No regional lymph node metastasis	No regional lymph node metastasis
N1	Locorregional lymph node metastasis	Locorregional lymph node metastasis
M0	No distant metastasis	No distant metastasis
M1	Distant metastasis	Distant metastasis

ENETS: European Neuroendocrine Tumor Society; AJCC: American Joint Committee on Cancer.