SEER Inquiry System - Question 20000851 Details

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Produced: 01/18/2026 7:52 AM

Question 20000851

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Inquiry Details

References:

ICD-O-3, 21, 32

Question:

Primary Site: What site code is used to classify a femur biopsy with pathologic diagnosis of "Ewing sarcoma/primitive neuroectodermal tumor (PNET)"? See discussion.

Discussion:

ICD-O-3 lists PNET as being site specific to C71._. The pathology report states "some authors consider both Ewing sarcoma and PNET to be the same histologic entity given that they share the same translocation between chromosomes 11 and 23."

Answer:

Code the Primary Site field to C40.2 [femur] based on Rule H in the ICD-O-3 that states, "Use the topography code provided when a topographic site is not listed in the diagnosis. This topography code should be disregarded if the tumor is known to arise at another site."

Cancer Site Category:

N/A

Data Item Category:

Primary site

Other Category:

N/A

Year:

2000