Imaging of gastroenteropancreatic neuroendocrine tumors

Table 2a Tumor node metastasis staging (gastric, duodenum, ampulla, jejunum, ileum, pancreas)

TNM staging	Gastric	Duodenum/ampulla/proximal jejunum	Pancreas	Lower jejunum/Ileum
Tx	Primary tumor cannot be assessed	Primary tumor cannot be assessed	Primary tumor cannot be assessed	Primary tumor cannot be assessed
T0	No evidence of primary tumor	No evidence of primary tumor	No evidence of primary tumor	No evidence of primary tumor
Tis	In situ tumor/dysplasia (> 0.5 mm)	-	-	-
T1	Tumor invades lamina propria or submucosa and </= 1 cm	Tumor invades lamina propria or submucosa and </= 1 cm	Tumor limited to pancreas and size < 2 cm	Tumor invades mucosa or submucosa and size </= 1 cm
T2	Tumor invades muscularis propria or subserosa or > 1 cm	Tumor invades muscularis propria or > 1 cm	Tumor limited to pancreas and size 2-4 cm	Tumor invades muscularis propria or size > 1 cm
T3	Tumor penetrates serosa	Tumor invades pancreas or retroperitoneum	Tumor limited to pancreas and size > 4 cm or invading duodenum or bile duct	Tumor invades subserosa
T4	Tumors invade adjacent structures (for any T, add M for multiple tumors)	Tumor invades peritoneum or other structures (for any T, add m for multiple tumors)	Tumor invading adjacent organs (stomach, spleen, colon, adrenal gland) or the wall or large vessels (celiac or superior mesenteric artery)	Tumor invades peritoneum/other organs (for any T, add m for multiple tumors)
Nx	Regional lymph nodes cannot be assessed	Regional lymph nodes cannot be assessed	Regional lymph nodes cannot be assessed	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis	No regional lymph node metastasis	No regional lymph node metastasis	No regional lymph node metastasis
N1	Regional lymph node metastasis	Regional lymph node metastasis	Regional lymph node metastasis	Regional lymph node metastasis
Mx	Distant metastasis cannot be assessed	Distant metastasis cannot be assessed	Distant metastasis cannot be assessed	Distant metastasis cannot be assessed
M0	No distant metastasis	No distant metastasis	No distant metastasis	No distant metastasis
M1	Distant metastasis	Distant metastasis	Distant metastasis	Distant metastasis