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Report Produced: 10/22/2025 08:59 AM

Report Question ID Question Discussion Answer Year
20081128

MP/H Rules/Histology--Breast: What is the histology code for the following?

4/21/03 Left breast: infiltrating ductal carcinoma, grade 3 micropapillary type. Tumor size: 3.5 cms; deep margin negative. Skin, nipple & areola positive for invasive ductal carcinoma. Dermal lymphatic invasion by carcinoma breast. Extensive intraductal component absent. 6+/6. See Discussion.

 How should histology be coded for a 2003 diagnosis and also for the same diagnosis in 2007 or later?

For a case diagnosed in 2003, code 8507/3 [Duct micropapillary carcinoma]. See Coding Complex Morphologic Diagnoses, revised August 2002, 3rd example on page 5 and page 3, #4.

For cases diagnosed 2007 or later, code 8507/3 [Duct micropapillary carcinoma]. Use rule H12.

 2008
20160002

MP/H Rules/Histology--Breast: Which is the correct histology code to use and which MP/H rule applies in the case of a single lumpectomy specimen that demonstrates two separate tumors with the following histologies.

1) Invasive lobular carcinoma

2) Invasive ductal carcinoma with tubular features

See discussion.

Does ductal carcinoma with tubular features qualify for Breast MP/H Rule H28? Or, is it more appropriate to strictly follow Table 2 (not a type of ductal tumor) and apply Rule H29, thus losing the lobular component?

Abstract a single primary using Rule M13. Assign 8523/3 using rule H29. The code for  invasive ductal carcinoma with tubular features (8523/3) is higher than the code for invasive lobular carcinoma (8520/3). H28 does not apply because 8523/3 is not included as a type of duct carcinoma on Table 2.

2016
20071122

MP/H Rules/Histology--Colon: How is histology coded when the final pathology diagnosis is "adenocarcinoma with extensive mucinous features" and the percent of mucinous features is not stated?

Code 8140 using rule H6. Rule H6 applies because the percent of mucinous is not specified.

2007
20170008

MP/H Rules/Histology--Colon: Is the code for invasive adenocarcinoma in a serrated adenoma 8213/3? The NAACCR Guidelines for ICD-O-3 Update Implementation, effective 1/1/14, provides new terms including 8213/0 for sessile serrated adenoma/sessile serrated polyp and 8213/3 for serrated adenocarcinoma. This would cause Site/Type and Histology overrides to be set. Coding 8210/3 would allow the case to be reported without overrides. See Discussion.

Pathology report 1/13/15, Histology - Transverse colon resection pathology = Invasive moderately differentiated adenocarcinoma. The invasive adenocarcinoma arises in a sessile serrated adenoma.

Assign 8213/3 to invasive adenocarcinoma arising in a sessile serrated adenoma. The instruction in SINQ 20120089 is still valid. The 2014 ICD-O-3 Update does not change this SINQ answer.

 2017
20130007

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.

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.

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.

2013
20110044

MP/H Rules/Histology--Corpus uteri: What are the histologies for the primaries to be reported when the endometrium contains two separate tumors composed of adenocarcinoma with multiple differentiations as well as a separate small focus of clear cell carcinoma? See Discussion.

 

The resected specimen showed, "Adenocarcinoma of endometrium with the following features: Histologic type: Endometrioid with squamous and focal clear cell differentiation. A second focus of endometrial adenocarcinoma is present in the fundus with admixed complex atypical hyperplasia in a polypoid, non-invasive mass. The second tumor is endometrioid with secretory differentiation. COMMENT: The tissue in between the two tumors is sampled, and contains foci of endometrial adenocarcinoma that is superficially present within the endometrium, as well as a small focus of clear cell carcinoma measuring 0.2 cm."

Per MP/H rules M17, this is counted as multiple primaries because the histology codes differ at the third digit: 8323/3, 8382/3, 8310/3. The Multiple Primary rules make no reference to the histology tables. There is also no rule to ignore the in situ tumor. In addition, the histology table in the 2007 MP/H Rules Manual for Other Sites does not include "secretory differentiation" as a type of GYN malignancy.

After consultation with our expert pathologist, the decision is report this case as a single primary. There was some confusion about how to apply the current MP/H rules to this pathology report given 1) the definition of M16 and M17 and 2) the likelihood for a single endometrial primary to present with several differentiations. According to our expert pathologist, "I would regard this case as a single endometrial primary with extensive endometrial involvement and several types of differentiation, all of which are seen in endometrial carcinomas."

Next, the Multiple Primary and Histology Coding Rules Manual is the correct source for coding histology for cases diagnosed 2007 or later.

The following steps are used to determine the histology code.

Open the Multiple Primary and Histology Coding Rules manual. For an endometrial primary, use the Other Sites Histo rules to determine the histology code because endometrium does not have site specific rules.

Start with the MULTIPLE TUMORS ABSTRACTED AS A SINGLE PRIMARY module, Rule H18. The rules are intended to be reviewed in consecutive order within the module from Rule H18 to Rule H31. You stop at the first rule that applies to the case you are processing.

Code the appropriate combination/mixed code (Table 2) when there are multiple specific histologies. GYN malignancies with multiple types of adenocarcinoma have histology coded to 8323/3 [mixed cell adenocarcinoma] per rule H30.

 2011
20140090

MP/H Rules/Histology--Endometrium: What is the correct histology code for an endometrial cancer described as "Adenocarcinoma with areas of squamous differentiation?"

Assign 8570/3 to adenocarcinoma with squamous differentiation of the endometrium. The most recent WHO classification does not list "adenocarcinoma" for tumors of the uterine corpus. WHO does state that "endometroid carcinoma of the usual type is a glandular neoplasm..." Further, WHO states "Endometroid carcinoma typically displays a glandular or villoglandular architecture..." Based on the WHO classification, the use of the term "adenocarcinoma" in this context can be interpreted as endometroid carcinoma.

2014
20091120

MP/H Rules/Histology--Esophagus: Should the modifying expression "with areas of" be used to code histology? See Discussion.

Patient was found to have two tumors in the esophagus. The large tumor was diagnosed as adenocarcinoma with areas of neuroendocrine differentiation (small cell carcinoma). The smaller tumor was diagnosed as small cell carcinoma. If we accept the "areas of" to be part of the diagnosis, rule H16 indicates that histology for the large tumor would be coded 8045 (combined small cell and adenocarcinoma). If we ignore the "areas of," then histology for the large tumor would be coded to 8140 (adenocarcinoma). Either way, when counting primaries, rule M17 would be applied and the two tumors would be classified as separate primaries. However, it seems that the two tumors are probably the same disease process since they both show small cell carcinoma.

For cases diagnosed 2007 or later, do not use the modifying expression "with areas of" to determine a more specific histology per rule H13 in the MP/H rules.

 2009
20130003

MP/H Rules/Histology--Head & Neck: How is the histology coded for a mammary analogue secretory carcinoma (MASC) of the parotid gland? See Discussion.

There is no histology listed in the ICD-O-3 for a mammary analogue secretory carcinoma. The pathologist stated that, "MASC is a recently described salivary gland tumor type which, as the name implies, resembles secretory carcinoma of the breast." Should the histology be coded 8550/3 [acinar carcinoma] or 8502/3 [secretory carcinoma of breast]?

Assign code 8502/3 [secretory carcinoma of breast].

Acinar carcinoma [8550/3] describes a very typical type of salivary gland tumor only. This histology code does not adequately capture the histology in this case which describes a secretory carcinoma that is similar to mammary cancer. Both of these elements are reflected in the histology code 8502/3 [secretory carcinoma of breast].

 2013
20150028

MP/H Rules/Histology--Head & Neck: Please clarify rule H3. The first statement is "Do not code terms that do not appear in the histology description". The second statement is "Do not code...unless the words...appear in the final diagnosis"

One of our pathology labs frequently will state "keratinizing squamous cell" in the microscopic description (histologic description), but only state "squamous cell carcinoma" in the final diagnosis. May we code from the histologic description if it's not in the final diagnosis?

Follow rule H3 and code squamous cell carcinoma for these cases unless you can obtain confirmation that these cases should be coded keratinizing squamous cell carcinoma from the lab and/or pathologist. Document this confirmation in your policies and procedures.

The MP/H rules were written with input from leading pathologists in each specialty area. Based on their expert opinion, we instruct registrars to code histology based on the information in the final diagnosis. The microscopic description may contain other terms, but the pathologist lists only the pertinent terms in the final diagnosis.

2015