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In the 2024 Solid Tumor Rules update, the small cell neuroendocrine carcinoma row in Table 2 was changed. The NOS histology became neuroendocrine carcinoma, NOS (8246) and both large cell and small cell neuroendocrine carcinomas (8013 and 8041, respectively) became the subtype/variants. This change impacts Rule H4 but Rule H4 was not updated. Rule H4 still refers to small cell neuroendocrine carcinoma as being the NOS histology.

In the prior STR versions, it was clear the tumor in question would be coded as 8045 per Rule H4 and Table 2. Considering Rule H4 was not updated according to the changes for Table 2, does histology 8045 still apply to this diagnosis?

There is currently no way to arrive at a histology for this case. Does Rule H4, bullet 3 need to be updated to indicate, “subtype/variant of neuroendocrine carcinoma mixed with any other carcinoma (does not apply to sarcoma)”?

In the 2018 ICD-O-3 Update Table, undifferentiated high-grade pleomorphic sarcoma and undifferentiated high-grade pleomorphic sarcoma of bone (C40_) were both listed as a New Term for histology 8830/3. There was no site restriction for a diagnosis of undifferentiated high-grade pleomorphic sarcoma. Therefore, it appears the diagnosis could easily be applied to a soft tissue tumor. This histology is used by pathologists in our region for soft tissue tumors as well as bone tumors. However, in the ICD-O-3.2 Table an entry (or synonym) was not provided for a tumor outside the bone.

The ICD-O-3.2 Table only lists undifferentiated high-grade pleomorphic sarcoma of bone for site codes C40_ and C41_ as a synonym for histology 8830/3. This also is not listed in the ICD-O-3.2 Implementation Guidelines. As a result, it is unclear whether a diagnosis of undifferentiated high-grade pleomorphic sarcoma of the soft tissue can be coded to 8830/3 and/or can be a synonym for the preferred term (8830/3, Malignant fibrous histiocytoma). Can a diagnosis of undifferentiated high-grade pleomorphic sarcoma of the soft tissue be coded to 8830/3, C49_ as it was per the 2018 ICD-O-3 Update Table?

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

In researching this, acral lentiginous melanoma is observed on the palms, soles and under the nails. To code to 8744, do we specifically have to see the word "acral" lentiginous melanoma?

In reference to the case below, does it make a difference if the CS T stage is known based on the primary excision but there is no clinical information in the record regarding the nodes or metastasis evaluation.

This scenario is seen on outpatient records of breast biopsies and melanoma excisions; i.e., punch bx followed by gross excision of the lesion but the medical record contains no clinical information or statement of everything else normal.

I&R Question 17625 2/16/2006

A patient was diagnosed with ductal carcinoma in situ by needle core biopsy of the right breast. There was no further information in the chart stating if or where the patient went for staging work-up and treatment. What are the codes for CS Extension, CS Regional Lymph Nodes and CS Distant Mets at Dx?

I&R Answer: Sufficient tissue must be taken to determine the T category. If this is the case, CS Extension = 00.

Unless the physician makes the statement that the physical exam is negative, code the CS Regional Lymph Nodes = 99 CS Distant Mets at DX = 99.

In previous STR versions and the ICD-O-3.2, SFT/hemangiopericytoma, WHO G1 is 8815/0 and only SFT/hemangiopericytoma, WHO G2 was 8815/1. However, Table 6 (Non-Malignant CNS, Specific Histologies, NOS, and Subtypes/Variants) was changed in the 2025 updates to indicate both G1 and G2 SFT/hemangiopericytoma are 8815/1.

No date range was provided for this change in the STR and the behavior of this tumor was not updated by the standard setters in other references (i.e., ICD-O-3.2). The behavior of G1 SFT/hemangiopericytoma was not updated in the 2025 ICD-O-3.2 updates. If the ICD-O-3.2 was the source of this change, should this have been documented in the 2025 NAACCR Implementation Guidelines? However, the 2025 NAACCR Implementation Guidelines indicates, "There are no ICD-O-3 changes for 2025." Is this behavior change in 2025 Solid Tumor Rules updates an error? Should the behavior of SFT/hemangiopericytoma, WHO G1 remain /0? 

In our registry, we code the primary site for such cases to the extra-lymphatic site if there is one extra-nodal site involved with disease and the patient does not have disseminated involvement of multiple extra-nodal sites. Is this correct? Example: A patient with a submandibular lymphoma and involved nodes undergoes a salivary gland excision and a modified radical neck dissection yielding 100 nodes.

In our region, pathologists often describe histology using the term phenotype. However, the use of the term phenotype is not discussed in the Solid Tumor Manual.

Example: Final Diagnosis of a colon tumor is invasive adenocarcinoma with a mixed phenotype, and the Diagnosis Comment states: The majority of the disease is poorly differentiated/signet ring cell phenotype.

Would the histology be coded to 8490 (signet ring cell carcinoma), if the majority of the tumor is a more specific histology described by the term phenotype?

In comparison to SINQ 20180022, this case does not mention VIN III anywhere in the final diagnosis. Is any mention of HGSIL in the final diagnosis reportable, even if it is qualified with a non-reportable term in parenthesis or CAP protocol?

In addition to the issue mentioned above, there is a SINQ answer that conflicts with the 2018 ICD-O-3 Histology Update table. SINQ 20130134 indicates indolent systemic mastocytosis is reportable for cases diagnosed 2010 and forward. There is no date restriction indicating the SINQ note applies only for cases diagnosed 2010-2017. Since indolent systemic mastocytosis was changed to borderline (9741/1) for diagnosis year 2018+, should the diagnosis year range be updated for this SINQ answer?

In a patient is diagnosed 1/29/08 with an invasive grade 3 of 3 papillary urothelial cell carcinoma arising in the depth of a calyx in mid portion of kidney, the primary site was coded C659 [Renal pelvis]. In 6/1/09 a TURBT showed three separate lesions on the right side of the bladder. The final diagnosis was high grade urothelial carcinoma in-situ with three tumors, the largest being 7mm. Per rule M8, the renal pelvis primary and subsequent bladder tumors are the same primary. Would the primary site be changed to C689 [Urinary system, NOS] when the bladder tumors were identified? Or is C689 only coded if more than one primary site is involved at diagnosis?