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Assign code 000 for Tumor Size--Clinical when EOD Primary Tumor is coded 800 (No evidence of primary tumor). Code 000 indicates no tumor was found since there was no clinical workup to identify this incidentally found cancer. This is a special instruction for cases coded 800 in EOD Primary Tumor. Text fields can be used to record details.

We recommend coding endometrium, C541, as the primary site for this case. While coding to fundus would not be incorrect, according to our expert pathologist consultant, "it is more appropriate in a setting in which the region of the uterus is of importance, e.g. with a myoma or a myosarcoma, or if the endometrioid carcinoma were NOT in the endometrium but arising in a focus of adenomyosis within the fundic myometrium."

Do not change the primary site in this situation. Since the review was done for a clinical trial and the change was not officially made in the patient's medical record, the primary site remains ovary for the cancer registry. Add an explanatory note in a text field for future reference.

Assign histology code 8249 for histology described as well differentiated NET G2. A synonym for NET of the appendix includes well-differentiated endocrine tumor/carcinoma according to WHO Classification of Tumors of the Digestive System, 4th edition. "Well differentiated" could apply to either NET G1 or NET G2.

Assign 8253/2 for adenocarcinoma in situ, mucinous. New codes were added in 2018 for mucinous adenocarcinoma in situ for lung cancer only as all cases were not invasive. Pathologist are discouraged from using the term BAC. In-situ lung tumors can now be identified as either mucinous or non-mucinous and the appropriate ICD-O code should be assigned based on diagnosis.

Abstract two primaries, one lobular carcinoma (8520/3) and another one Paget disease of the breast (8540/3) using the 2018 Breast Solid Tumor Rules, Rule M9: Abstract multiple primaries when the diagnosis is Paget disease with underlying tumor which is NOT duct. Example: Paget disease of the nipple with underlying lobular carcinoma are multiple primaries. Additionally, Table 2, Histology Combination Codes, Note 2 states: Lobular carcinoma and Paget are separate primaries (see Lobular carcinoma and any histology in Table 3 with exception of duct carcinoma/carcinoma NST/DCIS (and subtypes/variants) 8500 and Paget disease, in situ and invasive).

While not identified in the pathology of the mastectomy, the lobular carcinoma is likely underlying as it was identified in the axillary lymph nodes. The 2021 SEER Manual states: If the only pathologic specimen is from a metastatic site, code the appropriate histology code and the malignant behavior code (/3). The primary site and its metastatic site(s) have the same histology.

This is a single primary per Lung rule M7. First determine the histology for each tumor. Both tumors are coded 8140/3 because the histologies are a PATTERN. Reference: Coding Multiple Histologies (precedes histology rules) Instruction 2 says do not code pattern . If the word pattern was not in the diagnosis, you would code the specific histology.

When the choice is between ovary, fallopian tube, or primary peritoneal, any indication of fallopian tube involvement indicates the primary tumor is a tubal primary. Fallopian tube primary carcinomas can be confirmed by reviewing the fallopian tube sections as described on the pathology report to document the presence of either serous tubal intraepithelial carcinoma (STIC) and/or tubal mucosal invasive serous carcinoma.

If there is no information about the fallopian tubes, refer to the histology and look at the treatment plans for the patient. If all else fails, you may have to assign C579 as a last resort. Use text fields to document the details.

For additional information, see the CAP GYN protocol, Table 1: Criteria for assignment of primary site in tubo-ovarian serous carcinomas.

Assign code 22 for LUL wedge resection followed by a lingular-sparing LUL lobectomy and mediastinal lymph node dissection.  Code the lymph node surgery in Scope of Regional Lymph Node Surgery. We obtained input from an expert who agrees with this code. He states a lingula-sparing lobectomy is best coded as a segmentectomy because it is the same as an apical trisegmentectomy.

Assign Primary Site code C504 based on the location in the upper outer quadrant of the right breast, 10 o’clock, as opposed to code C501, around the areolar complex. The 2024 SEER Manual Breast Coding Guidelines advise that C502 - C505 are generally preferred over C501 when there is no other way to determine the subsite.