Appendix
Miscellaneous
Staging

Reviewer: Jaleh Mansouri, M.D. (see Authors page)

Revised: 1 March 2016, last major update August 2012

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Staging appendix
Table of Contents
General | Diagrams / Tables
General
  • In AJCC 7th edition, appendiceal carcinomas have a separate staging system from colorectal tumors
  • There are separate staging systems for appendiceal carcinoma and appendiceal carcinoid tumors

    Appendiceal carcinoma:
    • Primary tumor (T)
      • TX: Primary tumor cannot be assessed
      • T0: No evidence of primary tumor
      • Tis: Carcinoma in situ: intraepithelial or invasion of lamina propria, but not through muscularis mucosa into submucosa
      • T1: Tumor invades submucosa
      • T2: Tumor invades muscularis propria
      • T3: Tumor invades through the muscularis propria into the subserosa or into mesoappendix
      • T4: Tumor penetrates visceral peritoneum, including mucinous peritoneal tumor within the right lower quadrant, or directly invades other organs or structures
      • T4a: Tumor penetrates visceral peritoneum, including mucinous peritoneal tumor within the right lower quadrant
      • T4b: Tumor directly invades other organs or structures

    • Notes:
      • Direct invasion in T4 includes invasion of other segments of the colorectum by way of the serosa, e.g., invasion of ileum
      • Tumor that is adherent to other organs or structures grossly is classified cT4b; however, if no tumor is present in the adhesion, the classification should be pT1-3 depending on the anatomical depth of wall invasion

    • 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 4 or more regional lymph nodes

    • Notes:
      • A satellite peritumoral nodule or tumor deposit in the periappendiceal adipose tissue of a primary carcinoma without histologic evidence of residual lymph node in the nodule may represent discontinuous spread (T3), venous invasion with extravascular spread (T3, V1/2) or a totally replaced lymph node (N1/2)
      • Replaced nodes should be counted as positive nodes, while discontinuous spread or venous invasion should be counted in the site-specific factor tumor deposit
      • Examination should include 12 or more nodes, but classify as pN0 if < 12 nodes but all are negative

    • Distant Metastasis (M)
      • M0: No distant metastasis
      • M1: Distant metastasis
      • M1a: Intraperitoneal metastasis beyond the right lower quadrant, including pseudomyxoma peritonei
      • M1b: Nonperitoneal metastasis

      • G1: Well differentiated or mucinous low grade
      • G2: Moderately differentiated or mucinous high grade
      • G3: Poorly differentiated or mucinous high grade
      • G4: Undifferentiated

    Appendiceal carcinoid:
    • Primary tumor (T)
      • TX: Primary tumor cannot be assessed
      • T0: No evidence of primary tumor
      • T1: Tumor 2 cm or less in greatest dimension
      • T1a: Tumor 1 cm or less in greatest dimension
      • T1b: Tumor more than 1 cm but not more than 2 cm
      • T2: Tumor more than 2 cm but not more than 4 cm or with extension to the cecum
      • T3: Tumor more than 4 cm or with extension to the ileum
      • T4: Tumor directly invades other adjacent organs or structures; e.g. abdominal wall and skeletal muscle

    • Notes:
      • Tumor that is adherent to other organs or structures grossly is classified cT4; however, if no tumor is present in the adhesion, the classication should be pT1-3
      • Penetration of the mesoappendix does not seem to be as important a prognostic factor as the size of the primary tumor, and is not separately categorized

    • Regional lymph nodes (N)
      • NX: Regional lymph nodes cannot be assessed
      • N0: No regional lymph node metastasis
      • N1: Regional lymph node metastasis

    • Distant Metastasis (M)
      • M0: No distant metastasis
      • M1: Distant metastasis

      • G1: Mitotic rate <2 per 10 HPF; Ki-67 index < 2%
      • G2: Mitotic rate 2 to 10 per 10 HPF; Ki-67 index 3 to 20%
      • G3: Mitotic rate >10 per 10 HPF; Ki-67 index > 20%

    • Notes:
      • pM0 does not exist
      • Examination should include 12 or more nodes, but classify as pN0 if <12 nodes but all are negative
      • Mitotic rate based on counting 50 high-power fields (40x objective) in areas of highest activity

    • Stage grouping
      • Stage I: T1 N0 M0
      • Stage II: T2-3 N0 M0
      • Stage III: T4 N0 M0 or Any T N1 M0
      • Stage IV: Any T Any N M1
  • Diagrams / Tables

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    Appendiceal carcinoma