Reportability/Histology--Skin: Is a malignant spindle cell neoplasm consistent with atypical fibroxanthoma reportable for cases diagnosed 1/1/2023 and later, after thorough immunohistochemical work-up? See Discussion.
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?
Report malignant spindle cell neoplasms consistent with atypical fibroxanthoma as directed by Appendix E.1 of the 2023 and 2024 versions of the SEER Manual using 8830/3 (fibroxanthoma, malignant).
We will update the answer in SINQ 20190102. While the Other Sites Solid Tumor Rules address coding an NOS and specific histology sub-type/variant, this situation is not specifically addressed. We will also review the rules.
Solid Tumor Rules/Histology--Other Sites: Should an additional Note be added to Other Sites Solid Tumor Rules, Rule H12, to indicate that if the diagnosis is an NOS histology in a polyp, continue on through the rules or should Other Sites Rule H13 be moved ahead of Rule H12 to capture this specific histology? See Discussion.
The accuracy rate for SEER Workshop Case 04 (a duodenal invasive adenocarcinoma in an adenomatous polyp) was very low because Rule H13 was either being ignored or users were stopping at Rule H12 to code adenocarcinoma.
If the presence of an NOS histology in a polyp is still clinically relevant for the Other Sites module, this information will be missed due to the order of the H Rules, or the lack of clarification in Rule H12.
If a change is made to Rule H12 (Single Tumor: Invasive Only module), then changes must also be made to the Single Tumor: In Situ Only module and the Multiple Tumors Abstracted as a Single Primary module because both these modules include the same polyp coding H Rule.
The rule order is the same as in the previous MP/H rules. Will keep as is for now.
Assign codes adenocarcinoma in adenomatous polyp (8210), adenocarcinoma in villous adenoma (8261), and (adenocarcinoma in tubulovillous adenocarcinoma (8263) using Other Sites Solid Tumor Rule H12 or Rule H27 as these are specific invasive histology codes. Rule H13 applies to histology codes associated with polyps but associated with a histology term/code other than adenocarcinoma.