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Small bowel (small intestine)



Reviewer: Hanni Gulwani, M.D. (see Reviewers page)
Revised: 22 December 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.


● Does not apply to carcinoid tumors, GIST, lymphoma or sarcoma OR tumors in ileocecal value, Ampulla of Vater or Meckelís diverticulum

Primary tumor (T)

TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: Carcinoma in situ
T1a: Tumor invades lamina propria
T1b: Tumor invades submucosa *
T2: Tumor invades muscularis propria
T3: Tumor invades through the muscularis propria into the subserosa or into the nonperitonealized perimuscular tissue (mesentery or retroperitoneum) with extension 2 cm or less *
T4: Tumor perforates the visceral peritoneum or directly invades other organs or structures (includes other loops of small intestine, mesentery or retroperitoneum more than 2 cm, and abdominal wall by way of serosa; for duodenum only, invasion of pancreas or bile duct)

* Note: the nonperitonealized perimuscular tissue is, for jejunum and ileum, part of the mesentery and, for duodenum in areas where serosa is lacking, part of the interface with the pancreas

Regional lymph nodes (N)

NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in 1-3 regional lymph nodes
N2: Metastasis in four or more regional lymph nodes

● Note: involvement of the celiac nodes is considered M1 disease for carcinomas of the duodenum, jejunum and ileum

Distant metastasis (M)

M0: No distant metastasis
M1: Distant metastasis

Stage grouping

Stage 0: Tis N0 M0
Stage I: T1-2 N0 M0
Stage IIA: T3 N0 M0
Stage IIB: T4a N0 M0
Stage IIIA: Any T N1 M0
Stage IIIB: Any T N2 M0
Stage IV: Any T any N M1

End of Small bowel (small intestine) > Miscellaneous > Staging

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