Small intestine & ampulla


Staging-small intestine carcinoma

Editor-in-Chief: Debra L. Zynger, M.D.
Raul S. Gonzalez, M.D.

Last author update: 10 December 2020
Last staff update: 2 June 2021

Copyright: 2003-2024,, Inc.

PubMed Search: Small bowel staging[TI] "loattrfree full text"[sb]

Raul S. Gonzalez, M.D.
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Cite this page: Gonzalez RS. Staging-small intestine carcinoma. website. Accessed February 22nd, 2024.

Pathologic TNM staging of carcinomas of small bowel, AJCC 8th edition
Definition / general
  • Carcinomas, including neuroendocrine carcinomas, of the duodenum, jejunum and ileum are covered by this staging system
  • Use this system for duodenal / ampullary neuroendocrine tumors and this system for jejunum / ileum neuroendocrine tumors
Essential features
  • AJCC 7th edition staging was sunset on December 31, 2017; as of January 1, 2018, use of the AJCC, 8th Edition, 2018 is mandatory
ICD coding
  • C17.9: malignant neoplasm of small intestine, unspecified
Primary tumor (pT)
  • TX: primary tumor cannot be assessed
  • T0: no evidence of primary tumor
  • Tis: high grade dysplasia / carcinoma in situ
  • T1: tumor invades the lamina propria or submucosa
    • T1a: tumor invades the lamina propria
    • T1b: tumor invades the submucosa
  • T2: tumor invades the muscularis propria
  • T3: tumor invades through the muscularis propria into the subserosa or extends into nonperitonealized perimuscular tissue (mesentery or retroperitoneum) without serosal penetration
  • T4: tumor perforates the visceral peritoneum or directly invades other organs or structures (e.g., other loops of small intestine, mesentery of adjacent loops of bowel and abdominal wall by way of serosa; for duodenum only, invasion of pancreas or bile duct)

  • For jejunal / ileal pT3 tumors, the nonperitonealized perimuscular tissue is part of the mesentery
  • For duodenal pT3 tumors in areas lacking serosa, the nonperitonealized perimuscular tissue is part of the interface with the pancreas
Regional lymph nodes (pN):
  • NX: regional lymph nodes cannot be assessed
  • N0: no regional lymph node metastasis
  • N1: metastasis in one or two regional lymph nodes
  • N2: metastasis in three or more regional lymph nodes

  • Regional lymph nodes for the nonampullary duodenum include the retropancreatic, hepatic artery, inferior pancreaticoduodenal and superior mesenteric nodes
  • Regional lymph nodes for the jejunum or ileum include the mesenteric and superior mesenteric nodes; for the terminal ileum, the cecal and ileocolic nodes are also included
Distant metastasis (pM)
  • 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:T4 N0 M0
  • Stage IIIA:any T N1 M0
  • Stage IIIB:any T N2 M0
  • Stage IV:any T any N M1

Registry data collection variables
  • Primary tumor site (duodenum, jejunum, ileum)
  • Number of lymph nodes examined
  • Presurgical CEA
  • LVI
  • Microsatellite instability
  • Tumor grade
  • Presence of disease
  • Personal or family history of familial GI malignancies (familial adenomatous polyposis, Lynch syndrome, Peutz-Jeghers syndrome)
Histologic grade
  • GX: grade cannot be assessed
  • G1: well differentiated
  • G2: moderately differentiated
  • G3: poorly differentiated
Histopathologic type
Board review style question #1
Based on AJCC eighth edition criteria, a jejunal adenocarcinoma extending through the muscularis propria into the adjacent mesentery but without perforating the serosa would be staged as which of the following?

  1. pT1
  2. pT2
  3. pT3
  4. pT4
Board review style answer #1
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