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SEER Inquiry System - Report
Produced: 02/11/2026 8:39 AM
Question 20210030
Inquiry Details
References:
2021 SEER Manual. Appendix C, Breast Coding Guidelines
Question:
Primary site--Breast: Patient was diagnosed with invasive ductal carcinoma of the left breast. Site of mass is 2:00 to 3:00. What is the correct site code, C504 upper outer quadrant (UOQ) or C50.8 (overlapping)?
Discussion:
Answer:
Assign C504, UOQ, for a left breast primary mass at 2:00 to 3:00. See the illustration in the SEER Coding Guidelines for breast, https://seer.cancer.gov/manuals/2021/AppendixC/Coding_Guidelines_Breast_2021.pdf
Cancer Site Category:
Breast
Data Item Category:
Primary site
Other Category:
N/A
Year:
2021
