FY2027
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Excludes1 pair

C22.1 vs C24.0

C22.1 and C24.0 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on C22.1
malignant neoplasm of hepatic duct (C24.0)
C22.1

Intrahepatic bile duct carcinoma

Billable
Chapter 2
Neoplasms
Section
C15-C26
Use when the record says
  • Cholangiocarcinoma
Indexed under
  • Adenocarcinoma › bile duct type
  • Cancer › bile duct type liver
  • Cholangiocarcinoma › liver
  • Cholangiocarcinoma › unspecified site
  • Cystadenocarcinoma › bile duct
C24.0

Malignant neoplasm of extrahepatic bile duct

Billable
Chapter 2
Neoplasms
Section
C15-C26
Use when the record says
  • Malignant neoplasm of biliary duct or passage NOS
  • Malignant neoplasm of common bile duct
  • Malignant neoplasm of cystic duct
  • Malignant neoplasm of hepatic duct
Indexed under
  • Klatskin's tumor
  • Tumor › Klatskin's

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027