SEER Inquiry System - Search

In a situation like this with one area of metastatic involvement and an unknown primary, if there is no further information, we advise that the metastasis are "regional" until/unless proven otherwise. With this in mind, code the Mets at Diagnosis fields as 0, including the Mets at Diagnosis--Distant Lymph Node(s). This case should continue to be worked up to identify the primary site. If a primary site is identified later, update the abstract accordingly. In the meantime, use text fields to describe the situation.

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 correction to the SEER manual. Lymphomas originating in lymph nodes (C77) could have distant metastases to any site except lymph nodes. The following corrections to the manual apply now and will appear in the next version of the manual.

Remove C770-C779 from the instruction for assigning code 8 on the following pages.

Page 135 Mets at Dx--Bone

Page 137 Mets at Dx--Brain

Page 139 Mets at Dx--Liver

Page 141 Mets at Dx--Lung

Page 145 Mets at Dx--Other

Example

Biopsy of axillary lymph node: Diffuse Large B-Cell lymphoma. Lymph nodes involved above and below the diaphragm, multiple nodules seen in lung, lesions in liver. Bone marrow biopsy positive for DLBLC. Per Hematopoietic manual, primary site would be C778 for multiple lymph node regions involved.

Mets at Dx--Bone-0

Mets at Dx--Brain-0

Mets at Dx--Liver-1

Mets at Dx--Lung-1

Mets at Dx--Distant Lymph Nodes-8

Mets at Dx--Other-1

If you are collecting lymphovascular invasion (LVI) for thyroid cases, record "vascular invasion present (psammoma bodies only)" as vascular invasion (code 1, Lymphovascular Invasion Present/Identified) in the LVI data item. Use a text field to specify that this is vascular invasion by psammoma bodies.

Assign code 500 for EOD Primary Tumor for now.

We have confirmed with AJCC that "invasion of" but not "through" the visceral peritoneum maps to a T2 and not T3. Involvement of the visceral peritoneum for Summary Stage is Regional and does not make a distinction between "invasion of" or "invasion through." Any involvement of the visceral peritoneum is regional.

To correct this situation would require a new code, which would derive a T2/RE. That code will be added to the updates for 2023.

Code 500 will derive the appropriate Summary Stage of 2 (Regional). We are aware that this will derive the incorrect T; however, there is no work around at this time that will derive the correct T and Summary Stage, so we are defaulting to deriving the correct Summary Stage.

Use self-reported race as the priority when information on race is available. Use the associated text field to document why a particular race code was chosen when there are discrepancies in race information. Generally, race information is used from linkages when race data is missing or unknown, or to enhance data.

We will add clarification on linkages in the next SEER Manual update.

Lobular carcinoma was unintentionally excluded from M13. It will be added in the 2022 update. It is important registrars learn to use the tables and read the notes.

Abstract three primaries using 2018 Lung Solid Tumor Rules, Rule M6 and M8 as these are multiple synchronous tumors.

M6 (Subtypes in Column 3 of Table 3):

Adenocarcinoma, acinar predominant:

Primary Site: C343 (RLL)

EOD Primary Tumor: 300

Mucinous adenocarcinoma

Primary Site: C341 (RUL)

EOD Primary Tumor: 300

M8 (Separate rows in Table 3):

Large cell undifferentiated carcinoma:

Primary Site: C343 (RLL)

EOD Primary Tumor: 300

Note: The adenocarcinoma, NOS, along with the other subtypes, is on a different row than the large cell undifferentiated carcinoma and is already accounted for in Rule 6 as multiple synchronous tumors.

Do not include the adenocarcinoma, NOS in EOD Primary Tumor for the reportable primaries.

We consulted with an expert GYN pathologist. He confirmed our thinking that endometrial stripe or thickening does not represent clinical tumor size. We will add this to a future edition of the SEER manual for reference.

Abstract two primaries, invasive mucinous and DCIS, using 2018 Solid Tumor Rules for Breast, M14, as the discontinuous foci are separate tumors in this example and the histologies are on different rows of Table 3 of the rules.