SEER Inquiry System - Question 20021100 Details

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Produced: 10/15/2025 8:54 PM

Question 20021100

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Inquiry Details

References:

2004 SEER Manual, 73

Question:

Primary Site: How do we code the primary site for a malignancy that occurs in parenchyma located in an ectopic site? See discussion.

Discussion:

1. Patient presented with a subcutaneous nodule in right axilla. Pathologic impression by initial and reviewing pathologists is that the lesion represents a breast adenocarcinoma arising in ectopic mammary parenchyma. Subsequent breast biopsies were negative.

2. Patient presented with right branchial cleft cyst. The pathologist states the cyst is a primary thyroid adenocarcinoma arising in an ectopic focus of thyroid tissue. The subsequent total thyroidectomy is negative.

Answer:

Code the primary site to the location of the malignancy.

1. Code the Primary Site field to C76.1 [Axilla NOS].

2. Code the Primary Site field to C10.4 [Branchial cleft].

Cancer Site Category:

N/A

Data Item Category:

Primary site

Other Category:

N/A

Year:

2002