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SEER Inquiry System - Report
Produced: 02/02/2026 5:08 AM
Question 20020011
Inquiry Details
References:
2004 SEER Manual, 86
Question:
Discussion:
Answer:
For tumors diagnosed prior to 2007:
Assign code 8255 [Adenocarcinoma with mixed subtypes]. According to histology rule #4 for a single tumor on page 86 of the 2004 SEER manual, use a combination code if one exists.
For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.
History:
For cases diagnosed 1/1/01 to 12/2003, code the Histology field to 8255/3 [adenocarcinoma with mixed subtypes] based on rule A of the Coding Complex Morphologic Diagnoses. This is a new code that was added in the ICD-O-3.
Prior to 2001, "acinar adenocarcinoma [8550/3] and ductal adenocarcinoma [8500/3]" was coded to 8550/3 because both "acinar" and "ductal" are subtypes of adenocarcinoma and the histology should be coded to higher code of 8550/3.
