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The Solid Tumor Rules state that for cases diagnosed in 2022 and forward, p16 testing CAN be used to assign histology code 8085 (squamous cell carcinoma, HPV positive). The rules also state that for cases diagnosed prior to 1/1/2022, code 8085 MUST be based on ISH testing and not p16. ISH testing is not specifically addressed for 2022+ cases, but are we correct in assuming it can still be used as the basis for 8085?

Multiple CAnswer Forum posts and the AJCC 8th edition Head and Neck staging webinar indicate that the correct chapter/registry staging schema in this situation is determined ONLY by p16 results - not ISH testing, and therefore the Schema Discriminator 2 SSDI should be coded as 1 – p16 negative, regardless of ISH results.

While we understand that histology codes should not be changed based on staging criteria, there is a SEER/NAACCR edit, “Schema Discriminator 2, Head and Neck, Histology (NAACCR)” tag number N6802, that will not allow coding 8085 if Schema Discriminator 2 is coded as 1 (p16 negative). The edit does seem to be correctly enforcing the AJCC guidelines for choosing the staging schema, based on the sources noted above. Do the Solid Tumor or Site-Specific Data Items (SSDI) guidelines need to be modified for this situation?

Example: Patient had a 2023 nasopharyngeal mass biopsy showing “Nasopharyngeal non-keratinizing squamous cell carcinoma, undifferentiated type.” 

The Head and Neck Solid Tumor Rules (STRs) do not include an H Rule that instructs us how to code histology when there are two subtypes/variants present for a head and neck primary, nor does the STR define undifferentiated carcinoma as a subtype/variant for 8072.

The WHO Classification of Head and Neck Tumors states non-keratinizing nasopharyngeal carcinoma (non-keratinizing squamous cell carcinoma (SCC) is the most common subtype for nasopharyngeal ca, but that non-keratinizing can be subdivided into undifferentiated and differentiated subtypes.

Should histology be 8020 (undifferentiated carcinoma) or 8072 (non-keratinizing SCC)?

There are multiple possible entries (rows) for a tumor with a neuroendocrine component and non-neuroendocrine component, but these rows do not specify which primary sites are applicable. Row 1 (Combined small cell carcinoma, 8045) seems applicable to a prostate primary, but not to a GI primary since GI primaries are now generally referred to as MiNENs (mixed neuroendocrine non-neuroendocrine tumors), but Table 2 does not provide any instructions regarding how to determine the difference between 8045 and 8154 (or 8244).

For SEER Workshop Case 03 (mixed prostate case), many users selected 8154 or 8244 as the mixed histology code per Table 2, but these histology codes are not listed as applicable in Table 3 (Prostate Histologies). Per the WHO Blue Books, these histologies are not listed as applicable to the prostate.

How are registrars to determine the correct mixed code without site designations, especially if they don't have access to the WHO Blue Book or to a pathologist who may be able to clarify the codes?

SEER Program Coding and Staging Manual indicates high grade dysplasia of esophagus, stomach, and small intestine are reportable. The ICD-O-3.2 does not include “high grade dysplasia” as equivalent to “high grade squamous dysplasia.”

If reportable, would high grade dysplasia (NOS) that originates in the stomach and small intestine default to 8148/2, while esophageal high grade dysplasia (NOS) default to 8077/2?

Additional comments in this pathology report state "The entire case was sent in consultation to an ophthalmic pathologist. [Pathologist] assigns a conjunctival melanocytic intraepithelial neoplasia (C-MIN) score of 2-3 due to the upward pagetoid migration of small, dendritic melanocytes. A C-MIN score of 2-3 is between low-grade conjunctival melanocytic intraepithelial lesion (LG-CMIL; C-MIN 2) and high-grade conjunctival intraepithelial lesion (HG-CMIL; C-MIN 3). The older terminology for this lesion would be primary acquired melanosis (PAM) with mild to focally moderate atypia."

This term does not appear in the SEER Program Coding and Staging Manual (SPCSM), Appendix E1 of the SPCSM, or Solid Tumor Rules (specifically rule H3) . 

We know that physician TNM staging is not always accurate, and we also know that doctors sometimes use information in assigning their TNM which may not be available to registrars. Is it a discrepancy when the documentation in the chart is unclear or not definitive, yet the physician assigns a TNM that seems to incorporate that documentation? Or is a discrepancy an obvious conflict between chart documentation and the doctor’s staging – such as a mis-assignment of TNM category that doesn’t at all match with clear and complete medical record documentation, or the physician’s use of criteria that should be excluded from the TNM assignment per AJCC guidelines?

A real case example is a patient with breast carcinoma, imaging states 12 cm tumor with thickening of dermis, and thickening of morphologically suspicious internal mammary and level 1-2 axillary lymph nodes. Medical oncologist states locally advanced breast cancer with extensive changes involving skin thickening associated with the mass, at least stage IIIC based on imaging and exam findings, cT4 N3b. Only axillary nodes were sampled and found to be positive. Post-neoadjuvant therapy resection showed only focal DCIS. Per EOD guidelines, would the oncologist’s staging be a discrepancy with the chart documentation and therefore ignored, with EOD-Primary Tumor coded 200 for skin thickening, and EOD-Lymph Nodes 200 for involvement of axillary nodes only? Or would the doctor’s TNM be a clarification/confirmation of documentation terms that we otherwise would not code, with EOD-PT coded 400 for extensive skin involvement and EOD-LNs 600 for internal mammary + axillary nodes?

Patient was diagnosed March 2024 with high grade dysplasia of the gallbladder during excision for clinical history of acute cholecystitis and obstruction.

Per the STR, Table 10 for Gallbladder and Extrahepatic Bile Duct Histologies shows Biliary intraepithelial neoplasia, high grade as code 8148/2. High grade glandular intraepithelial neoplasia of the biliary tract is also code 8148/2.

Recent SINQ 20240021 (GI specific) indicates high grade dysplasia is reportable as high grade glandular intraepithelial neoplasia (8148/2) for stomach, small intestine, and esophagus. Does the same hold true for gallbladder? If so, then it appears there is a conflict between STR and Appendix E2.

However, using the logic of SINQ 20240021 for this site would appear to contradict Appendix E2 which indicates high grade dysplasia in sites other than stomach, intestine, and esophageal sites is not reportable.

If we can code high grade dysplasia of GI sites to 8148/2, should we accession high grade dysplasia of the gallbladder and other biliary sites in a similar manner? If so, then Appendix E needs to be modified.

1.  The 2022 and 2023 SEER Program Coding Manuals state under Histologic Type ICD-O-3: Beginning with cases diagnosed 01/01/2022 forward, p16 test results can be used to code squamous cell carcinoma, human papilloma virus (HPV) positive (8085) and squamous cell carcinoma, HPV negative (8086).

NAACCR 2023 Implementation Guidelines contain similar instructions on HPV histologies for cervix, vulva and vagina that are applicable back to 2022 (2021 for cervix).

The current Other Sites Solid Tumor Rules state on the Histology tables for anus, cervix, vagina, vulva, and penis and scrotum: "p16 is a valid test to determine HPV status and can be used to code HPV associated and HPV independent histologies." Since Other Sites Solid Tumor Rules apply to cases diagnosed 2023+, can p16 results only be used from 2023 onward, to code HPV-related histologies for primaries that fall under the Other Sites module? Or per the 2022 SEER Manual statement and NAACCR 2023 Implementation Guidelines, could a p16-confirmed HPV histology code also apply to a 2022 Other Sites case and if so, is that only for cervix, vulva, and vagina? Further complicating the matter are the 2024 ICD-O-3.2 update documents indicating these codes are valid 1/1/2024+ for the “Other Sites” penis and scrotum.

2.  Is using p16 testing for HPV-related histology codes ONLY allowed for sites in the Solid Tumor tables that contain the statements about p16 (Head & Neck Table 5, and the Other Sites tables noted above for anus, cervix, etc.)? Or could it apply to primary sites outside of those tables; for example, a 2022 pathology report from the ethmoid sinus C311 indicating an HPV-related histology based on p16 testing? The ICD-O-3 Annotated Histology lists include C310-C313 among the common site codes for 8085 and 8086. The Head and Neck Solid Tumor Rules “New for 2022” section and rule H1 Note 4 also mention that p16 can be used to code HPV histologies; these sections would seem to apply to all sites in that module, since only the more common histology codes are listed in the tables and if not, we are instructed to use ICD-O.

Imaging identified a mass involving the hypothalamus and pituitary gland and excision of the mass proved “histiocytosis.” The case was extensively reviewed, and the physician notes this patient has a pituitary tumor that is a “non-Langerhans cell histiocytosis,” or a “non-LCH histiocytic neoplasm.”

There is no histology for histiocytosis (NOS) or non-Langerhans cell histiocytosis. However, this does appear to be a non-malignant histiocytic neoplasm. If this were a Langerhans cell histiocytic neoplasm in the CNS it would be reportable. Should this non-Langerhans cell histiocytic neoplasm also be accessioned as a reportable CNS neoplasm? If so, how is the histology coded?