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SEER Inquiry System - Report
Produced: 06/21/2026 5:48 PM
Question 20200004
Inquiry Details
References:
#1: Solid Tumor Rules. Lung, July 2019 Update
#2: 2018 EOD Manual. SEER*RSA, v1.7
Question:
Solid Tumor Rules (2018)/Multiple primaries--Lung: How are Primary Site and EOD Primary Tumor coded when a patient is diagnosed with four invasive tumors in the right lung that represent three separate primaries, but the not otherwise specified (NOS) tumor and one of the specific subtype/variants are in separate lobes? See Discussion.
Discussion:
There are four invasive tumors in the right lung:
Large cell undifferentiated carcinoma in the right lower lobe (8012/3, C343);
Adenocarcinoma, acinar-predominant in the right lower lobe (8551/3, C343) that was 0.7 cm in size and limited to the lung;
Mucinous adenocarcinoma in the right upper lobe (8253/3, C341) that was 0.9 cm and limited to the lung;
Adenocarcinoma, NOS also in the right upper lobe (8140/3, C341) that was 1 cm and limited to the lung.
The Lung M Rules confirm the large cell undifferentiated carcinoma is a separate primary from the three adenocarcinoma tumors (Rule M8). The acinar adenocarcinoma and mucinous adenocarcinoma tumors are separate primaries (Rule M6). The adenocarcinoma, NOS tumor is the same primary as both the acinar and mucinous are adenocarcinomas (Rule M7).
How is Primary Site coded for both the acinar and mucinous adenocarcinomas if they represent multiple tumors reported as a single primary (when compared to the adenocarcinoma, NOS tumor)?
Should the adenocarcinoma, NOS tumor also be included when coding EOD Primary Tumor for both the right lower lobe acinar adenocarcinoma and right upper lobe mucinous adenocarcinoma primaries? Further follow-up with the physician is not possible.
Answer:
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.
