MP/H Rules--Breast: Is inflammatory breast cancer always one primary per lifetime? Or is a subsequent inflammatory breast cancer a second primary if diagnosed more than five years later?
For cases diagnosed 2007 or later, a diagnosis of inflammatory breast cancer more than five years after a previous diagnosis of inflammatory breast cancer is a separate (new) primary. See rule M5 in the Breast Multiple Primary Rules.
MP/H Rules/Histology--Colon: The final diagnosis on a path report for a colon specimen says: Is a colon specimen final diagnosis of carcinoma in situ in a serrated adenoma coded to 8010/2, 8210/2 or 8213/2?
For cases diagnosed 2007 or later, code the histology as 8213/2 [carcinoma in situ in a serrated adenoma].
The steps used to arrive at this decision are:
: Apply ICD-O-3 rule F (Matrix principle) and assign the behavior code /2 when the behavior assigned by the pathologist differs from the usual behavior as given in the ICD-O-3.
: Open the Multiple Primary and Histology Coding Rules Manual. Choose one of the three formats (i.e., flowchart, matrix or text) and go to the Colon Histology rules.
: Start at the SINGLE TUMOR module, Rule H1. The rules are intended to be reviewed in consecutive order within a module. Stop at rule H4. Code the histology as 8213/2.
Note: The histology 8213 (adenocarcinoma in serrated adenoma) will be added to rule H4 in the next revision.
MP/H Rules/Histology--Thyroid: How would the histology "micropapillary carcinoma" of the thyroid be coded for cases dx'd 2007 and after?
For cases diagnosed 2007 or later, assign code 8260/3 [Papillary adenocarcinoma] according to rule H14.
For thyroid cancer only, the term micropapillary does not refer to a specific histologic type. It means that the papillary portion of the tumor is minimal or occult, usually less than 1 cm. in diameter.
Ambiguous Terminology: Why was 60 days chosen for ambiguous terminology?
The Histology Task Force approved a 60 day time frame for ambiguous terminology.
The majority of cases are first identified by ambiguous terminology; for example, a patient has a mammogram that shows a lesion suspicious for cancer. That first indication of cancer prompts a work-up to either confirm or rule-out the cancer diagnosis.
The data item "Ambiguous terminology" is not intended to capture information on this routine method of detecting and diagnosing cancer. The 60 day time frame should keep these cases out of the ambiguous terminology data item.
The data item is intended to identify those cases where the cancer diagnosis is NOT confirmed during the work-up, but the case is still entered into the database. For example a patient who has a TRUS because of elevated PSA. The pathology from the TRUS says "Suspicious for adenocarcinoma of the prostate." The physician only documents that the patient is to return in 6 months for another PSA and TRUS. The registrar would enter this case into the data base because the word "suspicious" is on the ambiguous terminology list.
EOD 2018/EOD Regional Nodes--Oropharynx: Is code 550 missing “< equal to 6 cm” in the data item EOD Regional Nodes for Oropharynx HPV-Associated, Version 9? Otherwise, bilateral or contralateral lymph nodes with extranodal extension (ENE) that are >6 cm could fit into 550 OR 650.
Code 550 is missing “< equal to 6 cm.” In addition, code 650 should include ipsilateral lymph nodes as well.
Revised codes:
Code 550
CLINICAL ASSESSMENT only
Bilateral or contralateral lymph nodes, < equal to 6 cm WITH clinical evidence of ENE
Code 650
CLINICAL ASSESSMENT only
Ipsilateral, Bilateral or Contralateral lymph nodes > 6 cm WITH or WITHOUT clinical evidence of ENE
These changes will be implemented in Version 3.4 (October 2026). We apologize for the error.
First Course Treatment--All Sites: The patient has undergone part of the planned first course of treatment when a metastatic deposit is identified. If the patient continues with the planned first course of treatment, should the modalities of treatment given after the metastatic deposit is discovered be included in the coding of the first course of cancer-directed treatment fields?
Yes, those modalities should be counted as part of first course of cancer-directed treatment if the patient continues with the planned first course. For example, if patient has the originally planned type of surgery, radiation, or drug protocol, then code the given treatment as first course.
Caution: It is not a change in the treatment plan if the drugs are changed but the action of the drugs remains the same. This is still first course. However, if the treatment is changed from a chemotherapy drug to a hormonal drug following the discovery of the mets, do not code the hormonal therapy as first course.
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.
MP/H Rules/Multiple primaries--Ampulla of vater: Is this a new primary? Patient has intramucosal adenocarcinoma in a tubulovillous adenoma of the ampula of vater in Sept. of 2011. In May of 2012, patient has another ampullary adenoma with intraepithelial carcinoma (pTis) and an area suspicious for invasion. This is coded 8263/3.
Rule M14, Multiple in situ and/or malignant polyps are a single primary, precedes rule M15, An invasive tumor following an in situ tumor more than 60 days after diagnosis is a multiple primary, per the MP rules for 'Other sites',
Rule M14 applies. Abstract this case as a single primary.
Multiple Primaries (Pre-2007)--Skin: In a patient with Muir Torre syndrome, should each of 12 sebaceous carcinomas diagnosed from 1994-2005 be a new primary or should this process be one primary diagnosed in 1994?
For tumors diagnosed prior to 2007:
Follow the rules in the 2004 manual for determining multiple primaries. When the sebaceous carcinomas are in different sites (topography code difference in the first two numeric digits after the C), they are separate primaries. When the sebaceous carcinomas are more than two months apart, they are separate primaries.
For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.
Reportability/Histology--Breast: 2026: Is lobular neoplasia (atypical lobular hyperplasia) reportable? There is no mention of grade and or conclusive lobular carcinoma in situ (LCIS) statement given.
Do not report a case of atypical lobular hyperplasia of the breast until/unless it is definitively diagnosed as LCIS or another reportable neoplasm. WHO defines this as a non-invasive lobular neoplasia. Atypical lobular hyperplasia does not have an ICD-O code and is not equivalent to in situ.
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