Metastatic pediatric sclerosing epithelioid fibrosarcoma

Area of Science:

• Oncology
• Genetics
• Soft Tissue Sarcoma Research

Background:

• Sclerosing epithelioid fibrosarcoma (SEF) is a rare, aggressive soft-tissue sarcoma with poor response to conventional chemotherapy.
• SEF commonly affects adults but can occur in children, often presenting with local recurrence or metastasis.
• A frequent genetic hallmark of SEF is the EWSR1-CREB3L1 gene fusion, present in 80-90% of cases.

Observation:

• This report details the youngest SEF patient, a 3-year-old, with extensive bony and lung metastases.
• The patient underwent aggressive multimodal treatment, including surgery, radiotherapy, chemotherapy, and targeted therapeutics, with persistent disease progression.
• Comprehensive genomic analysis (whole-genome, whole-exome, deep-transcriptome sequencing) confirmed the EWSR1-CREB3L1 fusion as a consistent finding.

Findings:

• The EWSR1-CREB3L1 gene fusion was the sole consistent molecular feature identified across all sequencing analyses.
• Genomic analysis of the patient's tumor and metastatic tissues provided insights into SEF's molecular landscape.
• A novel primary SEF cell line was successfully generated, offering a new platform for research.

Implications:

• This case underscores the aggressive nature of SEF, even in pediatric patients.
• The consistent EWSR1-CREB3L1 fusion may serve as a diagnostic marker and a therapeutic target for SEF.
• Further research into the genomic findings and the new cell line could lead to improved therapeutic strategies for SEF.