SEER Inquiry System - Search

There was a 3.5 cm invasive adenocarcinoma tumor in the pancreatic head. There were four separate, sized pancreatic neuroendocrine tumors measuring 0.9, 0.7, 0.5 and 0.2 cm in the pancreatic body. There are multiple tumors with distinctly different histologies. However, Table 11 (Pancreas Histologies) does not include any entries for neuroendocrine tumors of the pancreas (e.g., pancreatic NET, WHO grade 1, histology 8240). While it would seem Rule M19 should apply as they’re distinctly different histologies, because PanNETs are not included in Table 11, it is not clear which M Rule applies to these multiple tumors.

If Rule M19 does not apply, we are left with Rule M21 (Abstract a single primary when there are multiple tumors that do not meet any of the above criteria). Are these separate tumors with distinctly different histologies really a single primary? Pancreatic neuroendocrine tumors are not an uncommon histology, is there a reason these were not included in Table 11?

Since the peripheral nerves are included in the Malignant CNS schema of the Solid Tumor Rules, neither the differences in subsite nor timing indicate these are separate primaries (Rule M10 indicates a single primary). However, these are separate MPNSTs in different sites and the tumors are not stated to be metastasis. Additionally, these are treated as separate primaries by the managing physician.

While the malignant CNS tumors do not take timing into account, is this correct for these peripheral nerve tumors that are often treated similarly to soft tissue tumors? Should Rule M8 be updated to include tumors in different peripheral nerve subsites?

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?

Rule M4 was added to the Other Sites M Rules to address diagnoses of small cell carcinoma following prostate adenocarcinoma, but Rule M4 states the diagnoses must be greater than one year apart.

In this situation, the diagnoses were less than one year apart and one must continue through the M Rules. The next M Rule that applies Rule M19: “Abstract multiple primaries when separate/non-contiguous tumors are on multiple rows in Table 2-21 in the Equivalent Terms and Definitions. Timing is irrelevant.” If one were to STOP at the first rule that applies, one would stop at Rule M19 which confirms the prostatic adenocarcinoma and small cell carcinoma are separate primaries, regardless of timing. If these are not to be accessioned as multiple primaries, does an Exception need to be added to M19?

Example:  A prostate core biopsy showed intraductal carcinoma in 09/2022, which is an in situ tumor.  A core biopsy again showed intraductal carcinoma in 12/2022.  The subsequent radical prostatectomy in 04/2023, revealed multiple foci of invasive prostate adenocarcinoma with extensive intraductal carcinoma. 

Per Solid Tumor Rules, Other Sites, Rule M3, acinar adenocarcinoma of the prostate is always a single primary.  Note 4, this rule applies to subtype variants of acinar adenocarcinoma listed in Table 3, which has intraductal/ductal as a variant subtype of acinar adenocarcinoma. Does rule M3 apply to incidence cases (an invasive tumor following an in situ tumor)?

The synoptic report calls this “Invasive adenocarcinoma with secondary Paget disease of anal mucosa and perianal skin.” The tumor size is listed as “2.1 x 1.7 x 0.7 cm, including associated advanced adenoma; size does not include the extent of the associated Paget disease, which extends for at least 2 cm distally.”  Clinically this is called an incidentally discovered Paget’s disease.

It is unclear if this is a collision tumor that should be abstracted as separate primaries, or if this is a single tumor with underlying Paget’s disease (similar to that described in Other Sites Rule H26). If this is a single rectal tumor, there does not appear to be an H rule for this scenario.

Based on the Solid Tumor Rules, we would make this two since it is over one year. According to a previous SINQ question 20110046, we are to code this as one primary. We see patients come back with multiple carcinoid tumors over the years and would like clarification.

Table 19: Vulva Histologies of the Other Sites Solid Tumor Rules does not include entries for either keratinizing or nonkeratinizing squamous cell carcinoma in the “Squamous cell carcinoma, NOS” row. However, these are two distinctly different histologies per the ICD-O-3.2.

All other Solid Tumor Rules schemas include an M Rule instructing one to abstract multiple primaries when separate/non-contiguous tumors are two or more different subtypes/variants in Column 3 of the Specific Histologies, NOS, and Subtype/Variants Table for the schema (e.g., Rule M6 for Lung). The timing of these tumors is stated to be irrelevant. The Notes confirm the tumors may be subtypes/variants of the same or different NOS histologies and tumors in column 3 are all distinctly different histologies (even if they are in the same row). However, the 2023 Other Sites schema appears to be missing this rule.

Should these distinctly different histologies be accessioned as separate primaries? Is an M Rule missing from the Other Sites schema to address distinctly different histologies?

The only Other Sites H Rule related to extramammary Paget disease is included in the Multiple Tumors Abstracted as a Single Primary module. Rule H28 instructs one to code the histology of the underlying tumor when there is extramammary Paget disease and an underlying tumor of the anus, perianal region, or vulva. Therefore, a vulvar extramammary Paget disease with underlying adenocarcinoma is coded as adenocarcinoma (8140/3), and not extramammary Paget disease (8542/3).

However, there is no M Rule confirming extramammary Paget disease and the underlying adenocarcinoma are a single primary (i.e., multiple tumors abstracted as a single primary) making it difficult for one to use the Multiple Tumors Abstracted as a Single Primary H rules module.

We recognize this is a longstanding histology coding rule, but how are registrars supposed to arrive at Rule H28 when the M Rules must be applied first and do not instruct one to accession a single primary? Moreover, if this is to be a single primary (per rule M2), why is there no H Rule in the Single Tumor module?

2021-Right pleural fluid:  Negative for carcinoma.

5/18/2021: Right iliac crest bone marrow core biopsy, aspirate smear, clot section and peripheral blood smear:  Hypercellular bone marrow, morphological findings are suspicious for a myeloproliferative neoplasm. Flow Cytometry: Slight immunophenotypic abnormalities of the myeloid cells. No abnormal B cell, T cell, or NK cell populations identified. Normal female karyotype. KARYOTYPE: 46,XX[20]. Negative for deletion of 13q14.3 (D13S319) by FISH. Negative for deletion of 13q34 (LAMP1) by FISH. Negative for hyperdiploidy involving chromosome 9 by FISH. Negative for t(9;22)(q34;q11.2) by FISH. Negative for deletion of the EGR1 gene on 5q31 by FISH. Negative for monosomy 5 by FISH. Negative for deletion of 7q31 by FISH. Negative for monosomy 7 by FISH. Negative for deletion of 20q12 by FISH. Negative for trisomy of chromosome 8 by FISH.

6/4/21-Left adrenal; biopsy: poorly-differentiated malignant neoplasm with extensive necrosis. Immunohistochemical stains show the neoplastic cells to be negative for CK7, TTF-1 and p63. Negative CK7 and TTF-1 would argue against a lung primary. Correlation with clinical and radiological findings is advised.

We are unable to contact the provider.