NTRK3 and congenital fibrosarcoma: FS-DFSP with atypical staining for CD34 could be confused with high-grade sarcomas, such as high-grade infantile fibrosarcoma (IFS) with ETV6-NTRK3 fusion, especially dedifferentiated liposarcoma (DDL) without a well-differentiated liposarcoma (WDL) component.