An official website of the United States government
Home
SEER Inquiry System - Report
Produced: 11/20/2025 11:30 PM
Question 20061034
Inquiry Details
References:
#1: 2004 SEER Manual, 74-75. #7
#2: ICD-O-3
Question:
Discussion:
Case 1 - CT: Mult pulm nodules, bilat pleural effusions; paraaortic, paracaval, celiac lymphadenopathy. Lytic lesions L4&L5.
Bx L3: Met pd adenoca. Based on the histopathologic features and the results of the immunostains, cholangiocarcinoma is regarded as the most likely primary. However, other possible primaries include pancreas, stomach, and (remotely) lung.
Should primary be coded as C26.9, digestive organ, NOS?
Case 2 - CT: Mult liver masses. Liver Bx: Mod diff adenoca. The most likely primary sites include cholangiocarcinoma, stomach and pancreas.
FDx per attending: Met adenocarcinoma to the liver, probably biliary origin.
What primary site code do we use?
Case 3 - Admitting Dx: Unknown primary with mets to lungs, liver and cerebellar area. Liver Bx: Met adenoca. The combination of morphological and immunohistochemical staining favor a colon primary. However other possibilities include cholangiocarcinoma and pancreatic ca.
Should we code site as C18.9 or C26.9?
Answer:
Code the primary site according to the physician's opinion. An ill-defined site code or an NOS code for the organ system is preferred over C809 [Unknown primary site] whenever possible. Code C809 only when there is not enough information to use an ill-defined or NOS code.
Case 1 and Case 2 - Assign code C249 [Biliary tract, NOS]. Based on the available information, the physicians believe these are most likely biliary primaries.
Case 3 - Assign code C189 [Colon]. According to the available information, the physician believes this is most likely a colon primary.
