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SEER Inquiry System - Report
Produced: 02/02/2026 7:04 AM
Question 20071077
Inquiry Details
References:
#1: 2007 SEER Manual, C-271, C-303 - C-310. Appendix C
#2: 2007 MP/H Rules. Colon (H20)
Question:
MP/H Rules/Multiple Primaries/Histology--Colon: How many primaries should be reported and how is the histology field(s) coded if the left colon contains two adenocarcinomas and one mucinous adenocarcinoma arising in a villous adenoma and each has a different level of invasion? See Discussion.
Discussion:
A patient had three tumors in the left colon including an 1) invasive well differentiated mucinous adenocarcinoma arising in tubulovillous adenoma with pericolonic subserosal fat invasion 8.5cm, 2) An infiltrative moderately differentiated colonic adenocarcinoma with invasion of muscularis propria 4cm and 3) an invasive moderately differentiated adenocarcinoma with invasion of muscularis propria, 1/69 nodes positive. The case was coded using rule M8 for one primary, but M10 contradicts; and H13 coding rule for histology 8263/3.
Answer:
For cases diagnosed 2007 or later:
Assuming that all tumors are in the left colon, there are three tumors:
Multiple Primary Determination
In the colon MP rules go to the multiple tumors module. Start with M3. Stop at M7 and abstract as a single primary.
Histology Code
Go to the histology coding rules, multiple tumors module, and start with H15. Stop at H20 which tells you to code the most invasive tumor. Tumor 1 is the most invasive according to the definition of most invasive in the 2007 SEER Manual, page C-271. Code 8263/3 [Adenocarcinoma in tubulovillous adenoma].
Cancer Site Category:
Colon
Data Item Category:
N/A
Other Category:
Multiple primaries
Year:
2007
