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The term “poorly differentiated carcinoma (NOS)” is listed as related to “undifferentiated carcinoma (NOS)” in the ICD-O 3.2. It is also listed in the Solid Tumor Rules for Urinary Table 2 (Urinary subtypes), Other Sites Table 16 (uterine corpus primaries) and Table 19 (vulvar primaries).

Are these the only sites in which one should code “poorly differentiated carcinoma (NOS)” as 8020 (undifferentiated carcinoma)?

How is histology coded if the only microscopic confirmation is from a metastatic site showing “poorly differentiated carcinoma” (NOS) or “invasive carcinoma, poorly differentiated” (NOS)?

Example 1: Primary pancreatic cancer diagnosed on imaging and confirmed with liver mets core biopsy showing “poorly differentiated carcinoma.” Immunostaining pattern was non-specific. No further workup or treatment was planned.

Other Sites - Table 11 (Pancreas Histologies) includes undifferentiated carcinoma (8020/3) as a valid histology; however, the synonyms/subtypes/variants do not mention poorly differentiated carcinoma. How should histology be coded for this case?

Example 2: Hemicolectomy with cecal tumor final diagnosis of “invasive carcinoma, poorly differentiated” and synoptic summary listing “Histologic type: Invasive carcinoma. Histologic grade: G3 of 4: poorly differentiated.”

Colorectal Table 1 (Specific Histologies and Subtypes/Variants) includes undifferentiated adenocarcinoma/carcinoma 8020 as a subtype of adenocarcinoma NOS. There is no mention of poorly differentiated in this context. How should histology be coded for this case?

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?

The race category in some hospital electronic medical record systems includes a combined category of “Native Hawaiian/Pacific Islander.” What race code should be used in a situation where the only available information is “Native Hawaiian/Pacific Islander?”

Starting for cases diagnosed in 2024, the SPCSM manual no longer requires the data items for clinical and pathologic tumor size.  Instead, it appears to align with the CoC data item of Tumor Size Summary.  The two manuals contradict each other when it comes to coding tumor size summary for neoadjuvant chemotherapy (NAC) treated cancers.  

STORE states: "If neoadjuvant therapy followed by surgery, do not record the size from the pathologic specimen. Code the largest size of the tumor prior to neoadjuvant treatment; if unknown code size as 999."  

2024 SPCSM states "If neoadjuvant therapy followed by surgery, do not record the size from the pathologic specimen. Code the largest size of the tumor prior to neoadjuvant treatment; if unknown code size as 999." It continues to state     

 12. Assign code 000 when…. (a) no residual tumor is found…(i) Neoadjuvant therapy has been administered and the resection shows no residual tumor &

14. Assign code 999 when...(d) Neoadjuvant therapy has been administered and resection was performed. Do not use a post-neoadjuvant size to code pathologic tumor size; however, you may use the clinical tumor size if available

It seems that we will lose the value of the tumor size summary if we code 000 when NAC is administered and there is no residual disease. 

Example: Patient has a 90 mm triple positive breast tumor and is treated with neoadjuvant TCHP (docetaxel/carboplatin/ trastuzumab/pertuzumab). After completing neoadjuvant therapy, the patient has a mastectomy with no residual disease noted on the final pathology report. 

Using the 2024 SPCSM instructions, code 000 for Tumor Size Summary instead of 090 for the clinical tumor size of 90 mm tumor noted before NAC was administered. This has the potential to affect data analysis, research, and clinical trial accrual.

Patient underwent excision of an oropharyngeal soft tissue mass revealing plasma cell neoplasm with extensive amyloid deposition. During work-up, bone marrow biopsy also revealed involvement by plasma cell neoplasm, with 5-10% of marrow cellularity. No amyloid seen in bone marrow. Patient was referred for radiation of the oropharyngeal mass. Per medical oncology qualifying best for the diagnosis of solitary extramedullary plasmacytoma with minimal marrow involvement. Decision made for observation by medical oncology in view of “minimal” bone marrow involvement. Question: Is rule M11 correct, and I abstract this case as a plasma cell myeloma, 9732/3, C421?

The patient had neoadjuvant chemotherapy (Carboplatin and Paclitaxel) concurrent with radiation per the managing physician. The physician stated the patient completed the neoadjuvant therapy; however, it was also noted that patient completed five cycles of chemotherapy, but the sixth cycle was held due to neutropenia.

The SEER Manual does not address how to code Neoadjuvant Therapy when the patient completed almost all the planned neoadjuvant therapy. It seems inappropriate to code Neoadjuvant Therapy as 2 (Started but not completed) simply because the patient did not have one cycle of chemotherapy but is otherwise felt to have completed neoadjuvant therapy per the managing physician. Does the managing physician’s statement of “completion” impact how this scenario is coded?

The Reportable Diagnosis List indicates "Lobular neoplasia grade II (LN II)/lobular intraepithelial neoplasia grade II (LIN II) breast (C500-C509)" is reportable.

The ICD-O-3.2 lists “Glandular intraepithelial neoplasia, grade II” and “Glandular intraepithelial neoplasia, low grade” as histology code 8148 with behavior of /0 (benign).

For example, a chest computed tomography showed multiple subsolid and ground glass pulmonary nodules measuring up to 6 mm; findings favored to reflect adenocarcinoma spectrum lesions.  A literature search seems to indicate that adenocarcinoma spectrum lesions include atypical adenomatous hyperplasia through invasive adenocarcinomas.