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Report Produced: 10/23/2025 04:05 AM

Report Question ID Question Discussion Answer Year
20110003 MP/H Rules/Histology--Colon: Which MP/H rule applies and what is the histology code for a "large cell neuroendocrine carcinoma (arising in adenocarcinoma)"? See Discussion.

Per the pathology report COMMENT section, "In addition to usual adenocarcinoma, a significant portion of this tumor displays features consistent with large cell neuroendocrine carcinoma, an aggressive neoplasm which has a poorer prognosis than adenocarcinoma of comparable stage."

Is histology coded to 8574/3 [adenocarcinoma with neuroendocrine differentiation] for this case?

For cases diagnosed 2007 or later:

Code histology to 8244/3 [composite carcinoid]. Rule H9 applies: Code 8244 [composite carcinoid] when the diagnosis is adenocarcinoma and carcinoid tumor. WHO describes these tumors as "mixed adenoneuroendocrine carcinoma (MANEC)." They have components of adenocarcinoma mixed with high-grade neuroendocrine carcinoma (NEC), which can be either small cell or large cell.

The next version of the MP/H rules for colon will make this clear by adding a note regarding this issue to Rule H9.

2011
20081044 MP/H Rules/Behavior--Melanoma of Skin: How are histology and behavior coded for a "malignant melanoma in situ with regression"? See Discussion. Per the microscopic portion of the path report, there is a zone of regression within the confines of the lesion, such that the possibility of antecedent invasive disease at the site cannot be ruled out with certainty.

For cases diagnosed 2007 or later:

Code malignant melanoma in situ with regression to 8720/2 [Melanoma in situ].

Code the histology according to the histologic type specified in the pathology report final diagnosis. Code the behavior as specified in the pathology report. Regression does not affect the coding of histology or behavior. See Melanoma Histology Coding rule H5. See 2007 SEER manual instructions for coding behavior, page 84.

 2008
20091010 MP/H Rules/Histology--Breast: What histology is coded when a final diagnosis on a lumpectomy specimen states "adenocarcinoma" but the regional lymph nodes show "poorly differentiated adenocarcinoma with signet ring differentiation"? See Discussion.

3/23 left breast mass bx: infiltrating lobular carcinoma.

6/22 left breast lumpectomy: infiltrating adenocarcinoma; sentinel lymph nodes with metastatic poorly differentiated adenocarcinoma with signet ring differentiation. Axillary resection with poorly differentiated metastasis in 8/9 nodes. The path micro states: tissue consists of sections of breast tissue having an infiltrating ca which in some areas infiltrates as small duct-like structures, and in other areas as small gland-like structures. In addition, there are foci in which the cells infiltrate in a single file fashion. In a few areas, cells having a signet ring appearance similar to those seen in the lymph nodes are encountered. In other areas, the signet ring appearance is not prominent. Areas of ductal or lobular ca in situ are not identified (the lymph node resection specimen shows 'signet ring appearance in some areas but no ductlike or tubular structures observed')

The comment on the lumpectomy path states: 'This is an unusual tumor in that it has histologic characteristics in varying areas, which would be consistent with infiltrating ductal carcinoma, infiltrating lobular carcinoma, tubular carcinoma or signet ring cell carcinoma. The metastatic material (8/9 total axillary lymph nodes) is most consistent with the poorly differentiated signet ring type portion of the tumor undergoing metastasis.'

For cases diagnosed 2007 or later:

Code the histology 8140 [Adenocarcinoma, NOS] using Breast rule H14.

Code the histology from the final diagnosis on the pathology report of the most representative specimen (the lumpectomy in this case). Do not code histology from the microscopic description. Code the histology from the primary site whenever available, not the metastatic site.

Comments on pathology reports can be used to code histology. However, in this case the final diagnosis is more definitive than the comments. The comment provides several choices and none of these appear in the final diagnosis; an indication that the pathologist was not able to clearly identify a more specific type in this case.

 2009
20081043 MPH rules--Rectum: How is the number of primaries to be determined when a treatment plan has been completed, but it is not possible to determine whether there was a disease-free interval between occurrences? See Discussion.

Patient diagnosed with adenocarcinoma of the rectum in March 2006, underwent chemo and radiation therapy as treatment. Patient seen in April 2007 for surveillance colonoscopy. HPI stated patient underwent chemorad with good results. Colonoscopy showed "persistent" disease. Abdominal perineal resection was done in May 2007. Path showed adenocarcinoma of the rectum.

Keeping in mind that we are not to use a clinical statement for determining recurrences, is the April 2007 occurrence counted as a new primary?

For cases diagnosed 2007 or later:

Do not abstract the 2007 events as a new primary. "Persistent disease" indicates there was never a disease free interval.

 2008
20110014 MP/H Rules/Histology--Corpus Uteri: Which MP/H rule applies in coding histology for a "high grade endometrioid adenocarcinoma with squamous differentiation (adenosquamous carcinoma)"? See Discussion. Is the pathology describing a specific histology, adenosquamous carcinoma [8560/3]? Or is this a combination/mixed histology code per rule H16? The Rule H16 instruction is to code a mixed histology code, 8323/3 [mixed cell adenocarcinoma] from Table 2 when two or more of the histologies are present (i.e., endometrioid and squamous in this case).

For cases diagnosed 2007 or later:

Endometrioid adenocarcinoma with squamous differentiation is coded to 8570 [Adenocarcinoma with squamous metaplasia].

The following row needs to be added to Table 2 in order to be able to correctly use the MP/H rules to reach this conclusion.

Column 1:   Endometrioid adenocarcinoma

Column 2:   Squamous metaplasia

                    Squamous differentiation

Column 3:   Adenocarcinoma with squamous metaplasia

Column 4:   8570

The change will be made in the next revision of the rules.

2011
20081046 MP/H Rules--Corpus uteri: How is histology coded for an endometrial tumor described as an "endometrioid adenocarcinoma with prominent squamous metaplasia"?

For cases diagnosed 2007 or later:

Endometrioid adenocarcinoma with squamous metaplasia is coded 8570 [Adenocarcinoma with squamous metaplasia]. This falls under the Histology Coding Rules for Other Sites, rule H17. The code for Endometroid adenocarcinoma is 8380. The code for Adenocarcinoma with squamous metaplasia is 8570. The histology with the numerically higher ICD-O-3 code is Adenocarcinoma with squamous metaplasia -- 8570.

 2008
20081129 MP/H Rules--Breast: What histology code should be used with invasive papillary carcinoma with cribriform carcinoma component? There is also DCIS adjacent to the invasive tumor, predominant cribriform and focal papillary patterns. This is a single breast tumor. See Discussion. Registry staff is divided between 8523 and 8255.

For cases diagnosed 2007 or later:

First apply rule H9, code the invasive. To determine the code for the invasive histology, start with rule H10 and stop at rule H15. Code the histology 8503 [papillary]. Papillary (8503) and cribriform (8201) are listed in Table 1 as specific duct types, but in this case they are invasive.

Table 1 and Table 2 will be clarified in the next version of the MP/H rules.

 2008
20091104 MP/H Rules/Histology--Esophagus: How is histology coded for a biopsy of the esophagus with a pathologic diagnosis of "adenocarcinoma, intestinal type" when there is no evidence of a gastric tumor in scans or EDG? See Discussion. There is a rule for colon to disregard "intestinal type" and code to adenocarcinoma (8140) but no rule for esophagus. How should histology for this esophageal case be coded?

For cases diagnosed 2007 or later:

Follow MP/H Other Sites Rule H11 and code 8144/3 [Adenocarcinoma, intestinal type]. Adenocarcinoma, intestinal type, is called that because it resembles the normal pattern of adenocarcinoma seen in the large intestines. It is not an indication of the location of the adenocarcinoma. We find that it is not uncommon in the sinuses, stomach, lungs, cervix, and many other organs.

 2009
20091018 MP/H Rules/Multiple Primaries/CS Extension: How many primaries are to be accessioned when tumors are present bilaterally in the pleura and fallopian tubes? See Discussion.

For both pleura and fallopian tube, the MP/H rules indicate that bilateral involvement of these sites should be coded as multiple primaries. However, both of these sites have CS extension codes that classify the contralateral disease as regional extension.

Is a case described as a left sided pleural mesothelioma that has right sided pleural disease coded as one or two primaries? How is CS coded?

For cases diagnosed 2007 or later:

For a pleural or fallopian tube primary, if there is tumor(s) on the left and separate tumor(s) on the right and neither is stated to be metastatic from the other, abstract as multiple primaries according to rule M8 for other sites. If both sides are involved, but there is only one tumor, rule M2 for other sites applies and this is a single primary. Code each primary separately in CS.

 2009
20071076 MP/H Rules/Histology--Thyroid: Regarding rule H15, is the mixed code 8340 [Papillary carcinoma, follicular variant] used when there are subtypes of these histologies described, such as a tumor diagnosed with follicular and papillary microcarcinoma or should 8341 [Papillary microcarcinoma] be used?

For cases diagnosed 2007 or later:

For coding purposes, this is a papillary and follicular combination that would be coded to the combination code 8340/3 [Papillary carcinoma, follicular variant].

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.

 2007