SEER Inquiry System - Question 20021003 Details

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Produced: 05/04/2026 10:12 AM

Question 20021003

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Inquiry Details

References:

2004 SEER Manual, 7-8

Question:

Multiple Primaries (Pre-2007): Whenever two hollow organs are diagnosed simultaneously with the same histology, one being invasive and the other in situ, can one assume that mucosal spread has occurred and that this situation represents one primary? In the absence of a physician statement, how do you determine mucosal spread from one organ to another?

Discussion:

Answer:

For tumors diagnosed prior to 2007:

Yes, this type of situation represents one primary. A tumor that is breaking down can be invasive in the center with in situ cancer at the margins. Occasionally the in situ margin can move into a contiguous organ with the same type of epithelium.

Physicians may describe mucosal spread in various manners. You will see the terms "intramucosal extension," "in situ component extending to," or statements of an invasive component in one organ, with adjacent/associated in situ carcinoma in a contiguous organ with the same type of epithelium. A frequent example of this process is bladder cancer extending into the prostatic urethra via mucosal spread.

For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.

Cancer Site Category:

N/A

Data Item Category:

N/A

Other Category:

Multiple primaries

Year:

2002