SITE SPECIFIC DATA ITEMS (SSDI)/ GRADE

Description

Cystic duct, distal bile ducts, and perihilar bile ducts all have the same ICD-O topography code (C240). However, for purposes of stage grouping in the AJCC 8th edition, they each have different chapters for stage. A schema discriminator is necessary to distinguish between these primary sites so that the appropriate chapter/schema is used.

Notes

**Note:** **Schema Discriminator for C240** * A schema discriminator is used to discriminate for primary site C240 (extrahepatic bile ducts) for the subsite in which the tumor arose. * **00242 : Cystic Duct (see code 3)** Per the AJCC Gallbladder Staging System, the gallbladder tapers into the cystic duct * **00250: Bile Ducts Perihilar (see codes 1, 5, 6, 9)** Per the AJCC Perihilar Bile Ducts Staging System, perihilar (or proximal) cholangiocarcinomas involve the main biliary confluence of the right and left hepatic ducts and comprise 50-70% of all cases of bile ducts carcinomas * **00260: Bile Ducts Distal ( see codes 4, 7)** Per the AJCC Distal Bile Duct Staging System, these tumors have their center located between the confluence of the cystic duct and common hepatic duct and the Ampulla of Vater (excluding ampullary carcinomas.)