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Report Produced: 10/08/2026 20:56 PM

Report Question ID Question Discussion Answer Cancer Site Category Data Item Category Year
20170007

MP/H Rules/Histology--Urinary System: How should histology be coded when there are multiple bladder, ureter and renal pelvis urothelial tumors including non-invasive papillary urothelial carcinoma in the left ureter, invasive papillary urothelial carcinoma invading the lamina propria in the bladder, and an invasive sarcomatoid urothelial carcinoma of the renal pelvis that invades the muscularis? See Discussion.

Per Rule M8, this is a single primary as there are multiple urothelial tumors as outlined in Table 1 (papillary urothelial carcinoma [8130] and sarcomatoid urothelial carcinoma [8122]) simultaneously present in multiple urinary organs (bladder, ureter and renal pelvis). As Rule M8 indicates these are a single primary, despite the histologies differing at the third digit (8130 vs 8122), then Rule H14 (Code the histology of the most invasive tumor) seems to be the most applicable histology rule. Following Rule H14 (in the Text version of the MP/H Rules), the histology would be coded as 8122 (sarcomatoid urothelial carcinoma) since the renal pelvis tumor was the most invasive tumor present.

However, in both the Matrix and Flowchart versions of the MP/H Rules, Rule H14 contains a note (missing from the Text version) that states that this rule should only be used when the first three numbers of the histology codes are identical (This is a single primary). Rule M8 clearly tells us these are a single primary, despite the differences at the third digit of the histology. Further defaulting to Rule H15 (Code the numerically higher histology code) in this case would ignore the histology of the tumor with the worse prognosis (the most invasive tumor). Was this note included in the Matrix and Flowchart versions in error?

Code the histology as 8122 according to the MP/H rules for Renal Pelvis, Ureter, Bladder, and Other Urinary, M8 and H14. Rule M8 states urothelial tumors in two or more of urinary sites including bladder and renal pelvis are a single primary. Rule H14 states code the histology of the most invasive tumors for multiple tumors abstracted as a single primary.

 Bladder Histology 2017
20170014

Reportability/Histology--Heme & Lymphoid Neoplasms: Is a physician statement that a patient has a malignant histiocytic disorder best described as Erdheim-Chester disease reportable? If reportable, should histology be coded to 9751/3? See Discussion.

The patient had a mediastinal mass biopsy showing fibrosclerotic tissue with patchy lymphohistiocytic foci and scattered plasma cells, followed by a retroperitoneal mass biopsy showing fibrohistiocytic infiltrate. Erdheim-Chester disease is not reportable per the Heme Database. However, the physician specifically states this is a malignant disorder.

Updated May 2026

For years prior to 2021, Erdheim-Chester disease is not reportable.

Starting in 2021, Erdheim-Chester disease is reportable and coded 9749/3. See the Hematopoietic database.

Heme & Lymphoid Neoplasms Histology 2017
20041021 Histology (Pre-2007)--Corpus Uteri: How should this field be coded when the D&C which shows "adenocarcinoma with mucinous and papillary features" and the TAH demonstrates only "endometroid carcinoma"? See Discussion. Should Histology be coded to 8380 [endometroid adenocarcinoma] because it is the most representative sample or to 8323 [mixed cell adenocarcinoma], per the Complex Morphology Coding Guidelines? The instructions in the Guidelines seem to imply that it is most important to represent combination histologies first, with majority (most representative sample) of tumor having a lower priority.

For tumors diagnosed prior to 2007:

Code Histology based on the pathology report from the most representative tissue. For the example above, code Histology to 8380 [Endometroid adenocarcinoma] based on the TAH/BSO pathology report.

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.

 Corpus uteri Histology 2004
20170022

MP/H Rules/Histology--Brain and CNS: What is the code for an embryonal tumor with multilayered rosettes. WHO shows the code as 9478/3, but this code is not available for use in the United States.

Assign ICD-O-3 code 9392/3 until code 9478/3 is implemented in 2018. Per our expert neuropathologist, embryonal tumor with multilayered rosettes was previously called ependymoblastoma.

 Brain and CNS Histology 2017
20160044

MP/H Rules/Histology--Sarcoma: What is the appropriate histology code for a final diagnosis of undifferentiated pleomorphic sarcoma and/or pleomorphic sarcoma, undifferentiated? See Discussion.

Does the Other Sites MP/H Rule H17 apply in this case, which results in coding the higher histology 8805/3 (undifferentiated sarcoma)? Or does the "undifferentiated" statement only refer to grade, which results in coding histology to 8802/3 (pleomorphic sarcoma)?

Assign 8802/34 to pleomorphic cell sarcoma/undifferentiated pleomorphic sarcoma. Pleomorphic is more important than undifferentiated when choosing the histology code in this case. Undifferentiated can be captured in the grade code.                           

Sarcoma Histology 2016
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.

Colon Histology 2013
20170040

MP/H Rules/Histology--Lung: What is the histology code for lung cancer case identified pathologically from a metastatic site that differs from the histology stated by the physician? See Discussion.

Bronchial washings were negative. Four lymph nodes were biopsied and found to have metastatic poorly differentiated neuroendocrine carcinoma. The treating oncologist calls it small cell carcinoma, extensive stage, and treats patient with carboplatin and VP-16 (etoposide) The MP/H rule says to take path/cyto from a metastatic site if no pathology/cytology available from the primary site. Is the physician's statement and treatment taken into consideration here?

Code the histology based on the pathology report from the lymph node biopsy for this case. Pathology has higher priority than a physician's statement for assigning histology code. Use text fields to document the physician's statement.

 Lung Histology 2017
20130197 MP/H Rules/Histology--Urinary System: What is the histology code for a 2007 and later diagnosis of papillary carcinoma of the urinary system organs? See Discussion.

Will histology code 8050 [papillary carcinoma, NOS] be used for cases diagnosed 2007 and later? The MP/H Rule H4 for urinary primaries states to code papillary carcinoma to code 8130, but Rule M6 includes tumors coded to 8050.

The IARC publication Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs uses code 8130 only for papillary carcinoma.

Code the histology to 8130 [papillary transitional cell carcinoma] for cases of papillary carcinoma of the urinary system diagnosed 2007 and later.

Histology code 8050 [papillary carcinoma, NOS] should not be used for papillary carcinoma of the urinary system diagnosed starting in 2007. Rule M6 includes this histology to take pre-2007 cases into consideration.

N/A Histology 2013
20061110 Histology (Pre-2007)--Head & Neck: How is a "sinonasal undifferentiated carcinoma (SNUC)" coded?

For tumors diagnosed prior to 2007:

Code histology to 8020 [carcinoma, undifferentiated]. "Sinonasal" refers to anatomic location of primary site not histology.

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.

 Head & Neck Histology 2006
20071073 MP/H Rules/Histology--Breast: How is histology coded for a single tumor with ductal and tubular features in only the invasive component and not in the in situ component? See Discussion.

A breast tumor diagnosed in Feb. 2007 is a single tumor with in situ and invasive components. The invasive component is diagnosed as ductal with tubular features.

The only rule that applies is H9 which says 'code the invasive histology.' Is it ductal (8500) or tubular (8211)? If you continue through the H rules, then H12 does not apply, because tubular is not a type of ductal. So then you end up at H17, which would make this 8523. Which code is correct?

For cases diagnosed 2007 or later, code the histology 8523 [duct mixed with other types of carcinoma].

After determining that the invasive histology is to be coded using rule H9, there is another decision to make in this case -- which invasive histology should be coded? Make a second pass through the histology rules, begining with rule H10. Stop at H17 and code 8523.

This advanced concept of a "second pass" through the rules is discussed in an online web training session called "Beyond the basics." Go to the SEER website to view this session http://www.seer.cancer.gov/tools/mphrules/training_advanced.html

 Breast Histology 2007