CS Extension: Small Intestine

Note 1: Ignore intraluminal or lateral extension to adjacent segment(s) of small intestine and code depth of invasion or spread outside the small intestine as indicated.

Note 2: 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 retroperitoneum.

Code Description TNM SS77 SS2000
00 In situ; noninvasive; intraepithelial Tis IS IS
05 (Adeno)carcinoma in a polyp, noninvasive Tis IS IS
10 Invasive tumor confined to mucosa, NOS, including intramucosal, NOS T1 L L
11 Invades lamina propria T1 L L
12 Invades muscularis mucosae T1 L L
13 Confined to head of polyp T1 L L
14 Confined to stalk of polyp T1 L L
15 Invasion of polyp, NOS T1 L L
16 Invades submucosa (superficial invasion) T1 L L
20 Muscularis propria invaded T2 L L
30
  • Localized, NOS
  • Intraluminal spread to other segments of small intestine or cecum
 T1 L L
40
  • Invasion through muscularis propria or muscularis, NOS
  • Extension through wall, NOS
  • Subserosal tissue/(sub) serosal fat invaded
  • Transmural, NOS
 T3 L L
42 Fat, NOS T3 RE RE
45
  • Adjacent connective tissue
  • Mesentery, including mesenteric fat, invaded less than or equal to 2 cm in depth or NOS
  • Nonperitonealized perimuscular tissue invaded less than or equal to 2 cm in depth or NOS
  • Retroperitoneum invaded less than or equal to 2 cm in depth or
  • NOS
 T3 RE RE
50 Invasion of/through serosa (mesothelium) (tunica serosa) (visceral peritoneum) T4 L RE
55 (50) + [(42) or (45)] T4 RE RE
60 For duodenum primary only:
  • Ampulla of Vater
  • Diaphragm
  • Extrahepatic bile ducts
  • Gallbladder
  • Pancreas
  • Pancreatic duct
 T4 RE RE
65
  • For duodenum primary only:
    • Blood vessel(s), major:
    • Aorta
    • Gastroduodenal artery
    • Portal vein
    • Renal vein
    • Superior mesenteric artery or vein
    • Vena cava
    • Greater omentum
    • Hepatic flexure
    • Kidney, NOS
    • Kidney, right
    • Liver, NOS
    • Liver, quadrate lobe
    • Liver, right lobe
    • Omentum, NOS
    • Transverse colon
    • Ureter, right
  • For jejunum or ileum primary only:
    • Colon, including appendix
 T4 RE RE
66 For duodenum primary only:
  • Stomach
 T4 RE RE
67 For all small intestine sites:
  • Abdominal wall
  • Mesentery invaded greater than 2 cm in depth
  • Non-peritonealized perimuscular tissue invaded greater than 2 cm in depth
  • Retroperitoneum invaded greater than 2 cm in depth
 T4 RE RE
68 For all small intestine sites:
  • Other segments of the small intestine via serosa
 T4 RE RE
70 For jejunum or ileum primary only:
  • Bladder
  • Fallopian tube
  • Ovary
  • Uterus
 T4 D D
80 Further contiguous extension T4 D D
95 No evidence of primary tumor T0 U U
99
  • Unknown extension
  • Primary tumor cannot be assessed
  • Not documented in patient record
 TX U U
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