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Produced: 03/01/2026 1:10 PM
Question 20130007
Inquiry Details
References:
2007 MP/H Rules
Question:
MP/H Rules/Histology--Colon: What rule applies and how is histology coded if a colon tumor is composed of moderately differentiated adenocarcinoma and neuroendocrine tumor, grade 1 (G1)? See Discussion.
Discussion:
Intestine, large -- moderately differentiated adenocarcinoma
Pathological stage: IIIA (T2 N1a Mx) -- Neuroendocrine tumor, G1
Addendum comment: The results of the immunochemical study are compatible with a neuroendocrine tumor, G1.
Answer:
For cases diagnosed 2007 or later, the correct histology code is 8244/3 [composite carcinoid]. The steps used to arrive at this decision are:
Step 1: Open the Multiple Primary and Histology Coding Rules Manual. Choose one of the three formats (i.e., flowchart, matrix or text). Go to the Colon Histology rules because site specific rules have been developed for this primary.
Step 2: Start at the SINGLE TUMOR module, rule H1. The rules are intended to be reviewed in consecutive order within a module. Stop at rule H9. Code the histology as 8244/3 [composite carcinoid] when the diagnosis is adenocarcinoma and carcinoid tumor.
Neuroendocrine tumor, grade 1 (G1) is synonymous with carcinoid tumor [8240/3] for the purpose of rule H9.
