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Code the Grade, Differentiation field to 9 [cell type not determined, not stated or not applicable]. For lymphomas, do not code the descriptions "high grade," "low grade," and "intermediate grade" in the Grade, Differentiation field. These terms refer to categories in the Working Formulation and not to histologic grade for lymphoma histologies.

Generally, for histologies other than Non-Hodgkin lymphoma, the Grade, Differentiation field is coded to 2 [low grade], 3 [intermediate grade] and 4 [high grade] for most cancers.

Please understand that AJCC sets the standards for TNM Staging and the Cancer PathCHART (CPC) initiative sets standards for the validity of site and morphology combinations. The statement in the AJCC manual “8240 and 8249 are excluded for topography code C160” means that these two histologies are not staged using the AJCC Staging System. As with numerous other reportable entities that are not staged by AJCC, the case is reportable and a Summary Stage should be assigned. Combinations of C160 with 8240 or 8249 are valid site/histology combinations for registry reporting and should not be discouraged from use if they correspond to the pathologist’s diagnosis. This goes for any other similar note in the AJCC manual. All CPC standards are enforced via the Primary Site, Morphology-Type, Beh ICDO3, 2024 (SEER) N7040 and Histologic Type ICDO3, Primary Site, Date of Diagnosis (NAACCR) N4911 data quality edits. Registrars can also look up the validity of site and morphology combinations using the CPC*Search tool:  https://seer.cancer.gov/cancerpathchart/search/tool/. 

It is important to remember the following.

• ALWAYS code the tumor histology stated by the pathologist/physician
• NEVER change the tumor histology to assign TNM
• Not all tumors or histologies can be staged per TNM
• Cases that cannot be assigned TNM are assigned a summary stage

For cases diagnosed 1998-2003:

Use the best information available, in this case, the clinical staging, to code EOD. Code the EOD-Extension field to 40 [Invasion through muscularis propria or muscularis, NOS] and the EOD Lymph Node field to 3 [Regional lymph node(s) NOS] because the case had a clinical stage of T3 N1. EOD is coded using the most extensive clinical or pathologic stage.

Code the Grade, Differentiation field to 1 [grade I] using the information from the BR score.

For cases diagnosed 1998-2003: Grade or differentiation information from breast pathology reports is used in the following priority order:

1. Terminology (well, moderately, poorly)

2. Histologic grade (grade I, grade II)

3. BR scores

4. BR grade

5. Nuclear grade

On the hierarchical list for coding breast grade, the first two priorities do not apply to this case, but the third (Bloom-Richardson scores) does. Add the BR information (2+1+1) for a total score of 4, which translates to BR low grade (code 1). The statement of "II/III" may be a typo that should state I/III.

Low grade appendiceal mucinous neoplasm (LAMN) is not reportable in 2018. See page 6, https://20tqtx36s1la18rvn82wcmpn-wpengine.netdna-ssl.com/wp-content/uploads/2018/02/2018-ICD-O-3-Coding-Table-Alpha-order-.pdf. Use cancer registry reportability instructions to determine reportability. Do not use the AJCC TNM manual to determine reportability.

For cases diagnosed prior to 1/1/2010:Code the Grade, Differentiation field to 9 [Cell type not determined, not stated or not applicable]. There is no combination code for B cell and T cell. There is also no hierarchy established for choosing one code over the other. Therefore coding such a case as a pure B cell or a pure T cell would misrepresent the phenotype.

For cases diagnosed 2010 forward, refer to the Hematopoietic and Lymphoid Neoplasm Case Reportability and Coding Manual and the Hematopoietic Database (Hematopoietic DB) provided by SEER on its website to research your question. If those resources do not adequately address your issue, submit a new question to SINQ.

For cases diagnosed prior to 2018

Abstract two primaries, Medullary (8510/3) and papillary microcarcinoma (8260/3). Other sites rule M17 applies.

For cases diagnosed 2007 or later, use the MP/H rules in order. Rule M6 comes before rule M7.

M6 states that bladder tumors with certain histologies are a single primary. It is a single primary regardless of timing if there is any combination of:

• papillary carcinoma [8050]

Rule M7 applies to bladder tumors with histologies other than those listed above. If you have such a case, rule M7 applies to in-situ tumors and to an in situ three years after an invasive.

Do not include the disease in the sequencing if the original hematolymphoid disease was not reportable at time of diagnosis.

The 2025 SEER Manual Sequence Number--Central Coding Instruction 1.a advises: A ‘reportable’ primary refers to the site/histology/behavior of the tumor and the years when reporting was required. Review of the reportability requirements in effect during the diagnosis year will be needed.

Do not code as a treatment. Record the cessation of immunosuppressive drug treatment in text to explain the patient’s change in disease status.