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SEER Inquiry System - Report
Produced: 10/20/2025 4:08 PM
Question 20110121
Inquiry Details
References:
2007 MP/H Rules
Question:
Discussion:
Per the CS Esophageal Schema, Note 4, there are now separate stage groupings for squamous cell carcinoma and adenocarcinoma. Should a tumor of mixed histopathologic type be classified as a squamous cell carcinoma?
Answer:
Do NOT use the Collaborative Stage Manual to determine the histology code. For CS STAGING purposes only, coding should be based on the squamous cell carcinoma component of this tumor.
The Multiple Primary and Histology Coding Rules Manual is the correct source for coding histology. For cases diagnosed 2007 or later, the following steps are used to determine the histology code:
Open the Multiple Primary and Histology Coding Rules manual. For an esophagus primary, use the Other Sites Histo rules to determine the histology code because esophagus does not have site specific rules.
Start at Rule H8 because this is an invasive histology (assuming this is a single tumor). which states that one should code the appropriate combination/mixed code from Table 2 when there are multiple specific histologies.
Find Other Sites for Table 2 under the Terms & Definitions section of manual.
Locate the appropriate mixed code for squamous cell carcinoma and adenocarcinoma in column 1. Per column 3, the correct histology is adenosquamous carcinoma. Per column 4, the correct histology is 8560/3.
