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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.

2012 Total abdominal hysterectomy - bilateral salpingo-oophorectomy

Primary Site – Ovary, Right

Histology - Small-Cell Carcinoma (Hypercalcemic Type), Large-Cell Variant

2024 Total abdominal hysterectomy - bilateral salpingo-oophorectomy

Primary Site – Ovary, Left

Histology - Small-Cell Carcinoma (Hypercalcemic Type), Large-Cell Variant

Patient has a 2021 left parotidectomy showing myoepithelial carcinoma ex-pleomorphic adenoma.  Is this coded to myoepithelial carcinoma (8982/3) or carcinoma ex-pleomorphic adenoma (8941/3)?  It is unclear how to arrive at the correct histology code using the current Solid Tumor Rules.

The ICD-O-3.2 indicates histology 8051 only applies to diagnoses of condylomatous carcinoma and warty carcinoma made prior to 2018. For penis cases diagnosed 2018 and later, these neoplasms should be coded as 8054. This is consistent with SINQ 20200003.

However, a new Table was added to the Other Sites schema in the 2024 Solid Tumor Rules update. Table 23 lists “Verrucous carcinoma / carcinoma cuniculatum / Warty carcinoma” as histology 8051. While verrucous carcinoma is still listed under histology 8051 in the ICD-O-3.2, warty carcinoma is not.

Does Table 23 need to be updated? Or is this an error in both the ICD-O-3.2 and SINQ 20200003?

The case in question represents an adenocarcinoma with neuroendocrine differentiation that arises in the absence of androgen-deprivation therapy. A 2023 journal article states, “We show that amphicrine prostate cancer is a unique entity and differs in clinical and molecular features from high-grade neuroendocrine carcinomas of the prostate. Our study highlights the need to recognize AMPC as a unique molecularly defined subgroup of prostate cancer.”

Should we be coding this with histology 8140 (Adenocarcinoma, NOS) because we have no specific code for an amphicrine carcinoma? Should we code this as 8045 (Mixed small cell carcinoma) because this is possibly the only way to capture both the adenocarcinoma and neuroendocrine components in a patient without previous treatment?

Our concern about using histology code 8574 (Adenocarcinoma with neuroendocrine differentiation) is that, while a valid histology code, this might confound the data if researchers are trying to separate the truly treatment-related tumors from other histologies captured under 8574.

This patient does not have a previous diagnosis of prostate adenocarcinoma nor a previous history of androgen-deprivation therapy.

Does the logic in the Other Sites Solid Tumor Rules (STRs) noted in SINQ 20200052 still apply? This SINQ confirms a diagnosis of mixed prostatic adenocarcinoma and small cell neuroendocrine carcinoma is 8045. This matches the STRs instructions for Rule H21 and Table 2 (Mixed and Combination Codes), row 1. Row 1 indicates a mixed small cell carcinoma and adenocarcinoma is combined small cell carcinoma (8045). For a patient without previous treatment, is this the correct mixed histology code?

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?

We included this histology in SEER Workshop Case 12 and the histology coding accuracy was less than 40%. From emails we received, it is clear that registrars are unaware that the "somatic type malignancy" can vary but code 9084 applies when the diagnosis is teratoma WITH any non-germ cell tumor component. It may be helpful to add a definition for "teratoma with somatic-type malignancy" (9084) to the Solid Tumor Manual.

Patient had a hemithyroidectomy with the final diagnosis above. There does not appear to be an Other Sites H rule or table that addresses this combination of histologies for thyroid primaries.