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SEER Inquiry System - Report
Produced: 01/08/2026 3:39 PM
Question 20190066
Inquiry Details
References:
Solid Tumor Rules, 32. Breast, July 2019 Update
Question:
Solid Tumor Rules (2018)/Histology--Breast: How is the histology coded for a metastatic carcinoma, consistent with primary breast carcinoma, when no other pathology information is available? See Discussion.
Discussion:
The 2018 Breast Solid Tumor Rules Equivalent Terms and Definitions - Changes from 2007 Multiple Primaries/Histology Rules states: Mammary carcinoma is a synonym for carcinoma no special type (NST)/duct carcinoma not otherwise specified (NOS) 8500. It will no longer be coded as carcinoma NOS 8010. Should metastatic carcinomas of breast origin be 8500, or is code 8010 (carcinoma NOS) more applicable because histology coding from metastatic sites is not as reliable?
Answer:
Code as 8500/3 as it is the only tissue available for this carcinoma associated with a breast primary. Breast carcinoma NST/NOS is now coded as 8500.
