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Previous SINQ 20091100 has a similar scenario and the instruction was to code as lentigo maligna (8742/2); however, it does not appear to be applicable to cases diagnosed after 2020.

The WHO Blue Book does not list melanoma, lentiginous type or lentiginous melanoma in situ as an alternate term for lentigo maligna and neither do the STR or the ICD-O-3.2.

The patient had residual tumor following the 2018 transsphenoidal resection and underwent an additional surgery after the residual tumor increased in size. Since pituitary adenoma/pituitary neuroendocrine tumor (PitNET) is a new malignant neoplasm for cases diagnosed 2023 and later, should this be a new primary per M5? Or do we disregard the change in behavior and apply rule M2 (single tumor is a single primary) for this scenario?

SINQs 20190083, 20180088, and 20130221 all indicate diagnoses of prostate adenocarcinoma, followed by a diagnosis of metastatic small cell carcinoma of the prostate are separate primaries because these are distinctly different histologies. Does this logic still apply for 2023 and later since Rule M4 was added to the Other Sites M Rules? Rule M4 states, “Abstract multiple primaries when the patient has a subsequent small cell carcinoma of the prostate more than 1 year following a diagnosis of acinar adenocarcinoma and/or subtype/variant of acinar adenocarcinoma of prostate.”

This patient has a 2018 diagnosis of prostate adenocarcinoma treated with radical prostatectomy, followed by a 2023 diagnosis of metastatic small cell carcinoma of the prostate diagnosed on a liver metastasis core biopsy. Rule M4 does not indicate whether it applies to subsequent biopsy confirmed metastatic tumor only. When a diagnosis of small cell carcinoma follows a diagnosis of prostatic adenocarcinoma, it is almost always confirmed in metastatic sites rather than in the primary site. Does the logic in the referenced SINQs above still apply for Rule M4?

The patient was not synchronously diagnosed with multiple tumors, but three separate tumors with three different histologies were diagnosed at different times and no more specific histology was provided for the NSCLC. The timing rules do not apply to this case (the tumors were not greater than 3 years apart and they were not synchronously/simultaneously diagnosed).

While NSCLC is a NOS histology for both adenocarcinoma and squamous cell carcinoma, it is unclear if Rule M8 should apply because NSCLC is not listed in Table 3 (Table 3 is not an exhaustive list). In some situations, Rule M8 would apply if the tumors were different histologies and one of the histologies was not listed in the Table. Does that logic still apply if one of the tumors is NSCLC? If NSCLC is excluded from Rule M8, is Rule M14 the appropriate M Rule for the 2022 NSCLC diagnosis?

The resection pathology report final diagnosis indicates this is both mixed mucinous and non-mucinous with a lepidic predominant component. The pathologist notes this is “Lepidic: 75%. Acinar: 25%.”  The percentage of the mucinous component is not documented.

Rule H1, Note 1, states “When mucinous carcinoma is mixed with another histology, such as adenocarcinoma and mucinous carcinoma, code mucinous ONLY when mucinous is documented to be greater than 50% of the tumor.” While mixed invasive mucinous and non-mucinous carcinoma is included in Table 2 (Combination/Mixed Histology Codes) without a required percentage, it is unclear whether one should move past Rule H7 and use Rule H8 to code this combination histology code. Rule H7 would instruct one to code the histology to lepidic adenocarcinoma (adenocarcinoma, lepidic predominant) based on the percentage of the lepidic component in the tumor. However, this does not address the mixed mucinous and non-mucinous diagnosis. Which H Rule and histology apply to this case?

In the examples below, are these a single or multiple primaries?

Example 1:

Tumor 1:  C509/left breast, 8520/2 (in situ lobular carcinoma), dx date-01/10/2019

Tumor 2:  C509/ left breast, 8500/3 (carcinoma NST), dx date-08/19/2021

Example 2:

Tumor 1:  C509, right breast, 8520/2, dx date 06/26/2014

Tumor 2:  C508, right breast, 8500/3, dx date-05/23/2019

There seems to be some conflicting info on this. In the 2020 Breast Rules there was a note add to the revision history. “M10 Same behavior requirement re-added.” Which is not in the rules now, nor was it noted to the revision changes in the last two change logs.

Inquiry 20200070 would seem to indicate that this is multiple primaries, but that contrasts with 20230010 which would seem to indicate a single primary, and an ASK A SEER Registrar question that we received a response to. I don’t see a scenario where rule M17, an invasive tumor DX more than 60 days after an in situ tumor would come into play.

If behavior no longer applies to rule M10, at what point did that change get made? Please advise.

Adenocarcinoma is a glandular tumor and the endocervix is generally the origin of glandular tissue for the cervix. However, if the only available information is pathology proving a single tumor overlapping the endocervix and exocervix, can we code the site to C530 instead of C538?

Applying the current primary site coding instructions, primary site would be coded as C538 because there is no specific statement of the tumor origin; the primary site coding instructions state the tumor is coded to an overlapping site in the absence of a specific statement of origin and there is no existing SINQ confirming the site can be assumed to be the endocervix based on the histology.

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.

In 2021, the patient was diagnosed with a non-reportable appendiceal LAMN.  Resection showed a tumor diffusely involving the appendix and perforating the visceral peritoneum, as well as extensive intraperitoneal metastasis.  In 2023, a lung wedge resection revealed metastatic mucinous neoplasm involving lung parenchyma and pleura, consistent with metastasis of the known appendiceal primary.  It is understood that intraperitoneal spread of an appendiceal LAMN does not make it reportable because the peritoneal disease is also non-invasive.  Does extraperitoneal metastasis of an appendiceal LAMN diagnosed prior to 2022 make it invasive disease and therefore reportable?