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SEER Inquiry System - Report
Produced: 04/30/2026 3:44 PM
Question 20190063
Inquiry Details
References:
WHO Class Soft Tissue & Bone, 236-237. 4th Edition
Question:
Solid Tumor Rules (2018)/Histology--Sarcoma: How is histology coded for a CIC gene rearrangement sarcoma? See Discussion.
Discussion:
According to the literature, CIC gene rearrangement sarcomas in young patients are soft tissue sarcomas with an aggressive clinical course and may have previously been grouped under the Ewing-like family of tumors or as undifferentiated round cell sarcomas. There is currently no guideline in the solid tumor rules for coding a CIC gene rearrangement sarcoma. However, coding the histology to 8800 (sarcoma, NOS) seems unlikely to capture the more aggressive nature of these tumors. Can a more specific histology be coded?
Answer:
Code as undifferentiated round cell sarcoma (8803/3).
The CIC rearrangement exists as a distinct molecular and clinical subset of small round cell tumors, and though similar, is felt to be a distinct entity from Ewing sarcoma. According to WHO Classification of Soft Tissues and Bone, 4th Edition, CID-DUX4 is a recurrent gene fusion associated with pediatric round cell undifferentiated soft tissue sarcoma (USTS). Although the genes involved in the fusion are different from those in Ewing sarcoma, the CIC-DUX4 protein has been shown to upregulate genes of the ETS family of genes thus providing a molecular link between Ewing sarcoma and round cell USTS. In contrast, there are strong arguments to suggest that Ewing-like sarcomas represent a separate and distinct entity.
