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SEER Inquiry System - Report
Produced: 02/09/2026 5:14 AM
Question 20010103
Inquiry Details
References:
2004 SEER Manual, C-471. Appendix C
Question:
Discussion:
Answer:
For tumors diagnosed prior to 2007:
Code "Infiltrating duct and mucinous carcinoma" to 8523/3 [Infiltrating duct mixed with other types of carcinoma] according to the instructions for coding a single tumor with complex histology in Appendix C of the 2004 SEER manual. Assign code 8523/3 when the diagnosis is duct carcinoma mixed with another type of carcinoma. Look for "and" or "mixed" in the diagnosis.
Code the Histology field for a "ductal carcinoma, mucinous type" to 8480/3 [Mucinous carcinoma].
The instructions for coding a single tumor with complex histology are to code the specific type if the diagnosis is "Duct carcinoma, _____ type."
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 breast cases diagnosed 1/2001 to 4/2003, ductal carcinoma, mucinous type will continue to be coded to the term that describes the majority of the tumor, mucinous (8480/3).
The ICD-O-3 code 8523/3, infiltrating duct and mucinous carcinoma is used to describe a tumor with mixed duct and mucinous carcinoma.
For breast cases diagnosed 5/2003 to 12/2003 No. Code the Histology field for a "ductal carcinoma, mucinous type" to 8480/3 [Mucinous carcinoma].
Rule 4 on page 3 of Coding Complex Morphologic Diagnoses, states you are to code the specific type if the diagnosis is "Duct carcinoma, _____ type."
"Infiltrating duct and mucinous carcinoma" is coded to 8523/3 per rule 3 on page 3 of Coding Complex Morphologic Diagnoses. Code 8523/3 is used if the diagnosis is duct carcinoma mixed with another type of carcinoma. Look for "and" or "mixed" in the diagnosis.
