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The ICD-O-3.2 Implementation Guidelines and ICD-O-3.2 Coding Table indicate that insulinoma, NOS has changed behavior from /0 to /3 for cases diagnosed 2021 and later. However, the ICD-O-3.2 Implementation Guidelines do not indicate whether this change applies to tumors described as above. Insulinomas are generally neuroendocrine tumors/neoplasms, so it seems any neuroendocrine tumor described as an insulinoma should be collected as 8151/3, but does that apply to an epithelioid tumor/neoplasm also described as insulinoma?

This question was prompted from preparing SEER*Educate coding exercises. We will use the answer as a reference in the rationales.

The diagnosis date is 2/24/14.  The pathology report of the pancreas shows: Well-differentiated neuroendocrine tumor (NET), low grade (WHO G1 of 3). Addendum: Ki-67 confirms low grade of pancreatic endocrine tumor (less than 2% Ki-67/MIB-1 index). Chromogranin confirms the endocrine nature of the tumor. The Pre and Post Op Diagnosis is pancreatic neuroendocrine tumor consistent with insulinoma. AJCC Stage as noted on path report: pT1, pNX, pM.

The physician states: The patient has a well-documented insulinoma. Biochemistries confirmed the disease and it is localized in the tail of the pancreas.

The issue with NETs is that pathology report reflects what is seen or what is quantified under the microscope; often, there is a specimen without the accompanying medical history and clinical signs. Many of these NETs are specified on the basis of the hormone, as usually measured in the blood, that is overproduced, something not seen microscopically. All of the islet cell tumors are NETs. The insulinoma in the example above is a well-differentiated NET that is causing insulin to be over-produced. Thus, the diagnoses are not discordant; insulinoma is a more specific NET.

Appendix E1 of the 2018 SEER manual references a similar diagnosis as being reportable for vulva and vagina only. However, the WHO Classification of Tumors of the Urinary System and Male Genital Organs (4th ed) does include high grade penile intraepithelial neoplasia as a synonym for 8077/2.

Example: An October 2017 glans penis biopsy final diagnosis was reported as: Undifferentiated (Warty-Basaloid) penile intraepithelial neoplasia.

In January 2018, an additional penile glans biopsy final diagnosis was reported as: At least squamous cell carcinoma (SCC) in situ (HGPIN). Foreskin circumcision on the same pathology report shows SCC in situ.

It is unclear whether the term undifferentiated is synonymous with high-grade for the purposes of determining penile intraepithelial neoplasia (PIN/PEIN) reportability and diagnosis date.

Appendix E1 in both the 2023 and 2024 SEER Program Coding and Staging Manual (SPCSM) lists these malignant spindle cell neoplasms, consistent with atypical fibroxanthoma, as reportable when other tumors have been ruled out with immunohistochemistry. This contradicts both SINQ 20190102 and the Solid Tumor Rules (STRs) general instructions indicating ambiguous terminology (e.g., “consistent with”) cannot be used to code the more specific histology when there is a NOS (malignant spindle cell neoplasm, 8004/3) and a more specific (malignant atypical fibroxanthoma, 8830/3) histology.

These tumors are typically diagnosed and treated in dermatology offices, so further chart review or confirmation by a physician is not possible for central registries.

As non-melanoma skin primaries are included in the Other Sites schema, and this schema was updated for cases diagnosed 2023 and later, which instruction applies to 2023+ diagnoses? Should these continue to be collected per Appendix E1 despite the conflict with the STR Manual and SINQ? If these are reportable, should the SINQ and STR Manual be updated to reflect this? Or should these be non-reportable per the STR Manual and SINQ?