Source 1: ICD-O Third Edition, Second Revision Morphology
Notes: 2021 ICD O 3.2 Coding Table Excel, 10/01/2020
Histology/Biliary tract--Ampulla of Vater: What is the histology code for Intra ampullary papillary-tubular neoplasm in association with microinvasion? See discussion.
Patient was diagnosed on 01/2020, and primary site on the pathology report is Ampulla of Vater (C241). Synoptic Report states histology as: Intra ampullary papillary-tubular neoplasm in association with microinvasion.
I have reviewed the ICD-O-3 coding table and found histology Intraductal tubulopapillary neoplasm (C25_) code 8503/2. Based on the Matrix principle (Rule F on the ICD-O-3), I will change the behavior to 3 and code as 8503/3. If I look in ICDO-3, Tubulopapillary adenocarcinoma is coded 8263/3.
Assign code 8163/3. Based on the microinvasion, the correct term for this neoplasm is pancreatobiliary-type carcinoma. Unfortunately, WHO did not provide all synonyms or related terms for some of the new ICD-O codes. Pathologists may continue using non-preferred terminology as well.