Schema Discriminator 1: Primary Peritoneum Tumor

This input is used in derivation

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.

NAACCR Item

NAACCR #3926

Metadata

SSDI
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 patient record Small Intestinal, Esophageal, Colorectal, Mesenteric and Peritoneal GIST
<BLANK> Primary Site is NOT C481, Discriminator is not necessary