Data Last Updated: Sept. 13, 2023

Schema Discriminator 1: Primary Peritoneum Tumor

This input is used for staging

Notes

**Note:** Since both omental and peritoneal gastrointestinal stromal tumors (GIST) are coded with the same ICD-O-3 topography code (C481), this data item must be used to identify the appropriate AJCC stage table.
Code Description Stage Table
1 Mesentery
Mesoappendix
Mesocolon
Pelvic peritoneum
Rectouterine pouch
- Cul de sac
- Pouch of Douglas

Other specified peritoneal site
Small Intestinal, Esophageal, Colorectal, Mesenteric and Peritoneal GIST
2 Omentum Gastic and Omental GIST
9 Unknown or no information
Not documented in medical record
Small Intestinal, Esophageal, Colorectal, Mesenteric and Peritoneal GIST
<BLANK> Primary Site is NOT C481, Discriminator is not necessary