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We would like to confirm that the correct histology code is 9431/1 per ICD-O-3.2, as the Non-Malignant CNS Solid Tumor Manual lists the histology code as both 9431/1 (pages 301 and 303 of the combined manual), but also shows it as a synonym for 9421/1 – Diffuse astrocytoma, MYB- or MYBL1 altered (page 304).

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?

The term “poorly differentiated carcinoma (NOS)” is listed as related to “undifferentiated carcinoma (NOS)” in the ICD-O 3.2. It is also listed in the Solid Tumor Rules for Urinary Table 2 (Urinary subtypes), Other Sites Table 16 (uterine corpus primaries) and Table 19 (vulvar primaries).

Are these the only sites in which one should code “poorly differentiated carcinoma (NOS)” as 8020 (undifferentiated carcinoma)?

How is histology coded if the only microscopic confirmation is from a metastatic site showing “poorly differentiated carcinoma” (NOS) or “invasive carcinoma, poorly differentiated” (NOS)?

Example 1: Primary pancreatic cancer diagnosed on imaging and confirmed with liver mets core biopsy showing “poorly differentiated carcinoma.” Immunostaining pattern was non-specific. No further workup or treatment was planned.

Other Sites - Table 11 (Pancreas Histologies) includes undifferentiated carcinoma (8020/3) as a valid histology; however, the synonyms/subtypes/variants do not mention poorly differentiated carcinoma. How should histology be coded for this case?

Example 2: Hemicolectomy with cecal tumor final diagnosis of “invasive carcinoma, poorly differentiated” and synoptic summary listing “Histologic type: Invasive carcinoma. Histologic grade: G3 of 4: poorly differentiated.”

Colorectal Table 1 (Specific Histologies and Subtypes/Variants) includes undifferentiated adenocarcinoma/carcinoma 8020 as a subtype of adenocarcinoma NOS. There is no mention of poorly differentiated in this context. How should histology be coded for this case?

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?

The WHO Classification of Hematopoietic Tumors (Blue Book), 5th edition states: “Rare cases of classic follicular lymphoma with cytological features of follicular lymphoma (FL) grade 3A can present with a prominent diffuse pattern. In the previous edition, such cases were defined as diffuse large B-cell lymphoma (DLBCL). Currently, it is uncertain whether such cases should be classified as FL or diffuse large B-cell lymphoma; and in such cases, individual treatment choices should be made in multidisciplinary conference settings taking into consideration clinical, laboratory, and imaging parameters. The presence of diffuse areas composed entirely or predominantly of large cells, however, warrants a diagnosis of diffuse large B-cell lymphoma.”

Our concern is that the Hematopoietic (Heme) Manual and Database do not provide instruction for coding this scenario. We hesitate to interpret the terms “equivalent to” as ambiguous because one could argue it is unambiguous. Barring this argument, the M and H rules would indicate this is a diagnosis of diffuse large B-cell lymphoma. However, the physician does not seem to agree with the pathologist.

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 underwent excision of an oropharyngeal soft tissue mass revealing plasma cell neoplasm with extensive amyloid deposition. During work-up, bone marrow biopsy also revealed involvement by plasma cell neoplasm, with 5-10% of marrow cellularity. No amyloid seen in bone marrow. Patient was referred for radiation of the oropharyngeal mass. Per medical oncology qualifying best for the diagnosis of solitary extramedullary plasmacytoma with minimal marrow involvement. Decision made for observation by medical oncology in view of “minimal” bone marrow involvement. Question: Is rule M11 correct, and I abstract this case as a plasma cell myeloma, 9732/3, C421?

Note 1 states that this histology is treatment-related neuroendocrine prostatic carcinoma demonstrating complete neuroendocrine differentiation or partial neuroendocrine differentiation with adenocarcinoma after androgen-deprivation therapy (ADT). Conversely, Note 2 says to code 8574/3 only when there is no history of previous prostate adenocarcinoma or history of androgen-deprivation therapy.

The WHO Blue Book does confirm this is a treatment-related histology, so it seems we would only use this for an adenocarcinoma with neuroendocrine differentiation (or even possibly a mixed histology tumor with adenocarcinoma and small cell carcinoma components) if the patient had previous treatment.

If this histology is treatment-related, why would we use this code for a patient without a history of prostate adenocarcinoma or androgen-deprivation therapy? Should Note 2 be corrected?

Does this histology apply to a post-treatment diagnosis of mixed adenocarcinoma and small cell carcinoma? If yes, should this clarification be added?

The 2024 Solid Tumor Rules, Table 5: Tumors of the Oropharynx, Base of Tongue, Tonsils, Adenoids contain notes that say beginning 1/1/2022, keratinizing or non-keratinizing SCCs, HPV positive or HPV negative, are coded 8085 or 8086, respectively, for sites listed in the Head and Neck Solid Tumor Rules, Table 5 only.

Table 5 introductory section also states for cases diagnosed 1/1/2023 forward: “When the diagnosis is a subtype/variant of squamous cell carcinoma and HPV status is also noted, code the subtype/variant.” This latter instruction is also included in Other Sites Table 23 (Penis and Scrotum Histologies) as a “Penis Coding Note.”

Do these instructions ONLY apply to sites on those tables (and only to Penis or to Scrotum also in Table 23)? How should we code HPV-related keratinizing/non-keratinizing or other subtype/variant SCCs, for sites NOT on those tables, given the fact that only the more common histologies are listed in the Solid Tumor tables? For example, we recently reviewed a case with HPV-positive basaloid squamous cell carcinoma of the anus (C21.0).