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Updated: Jul 20, 2026
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Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models
Published on: May 17, 2024
Peripheral primitive neuroectodermal tumor with postchemotherapy neuroblastoma-like differentiation.
Annikka Weissferdt1, Kim Neuling, Martin English
1Birmingham Children's Hospital, Department of Histopathology, West Midlands, UK. aweissferdt@doctors.org.uk
Summary
This study details an 11-year-old girl with a soft tissue peripheral primitive neuroectodermal tumor/Ewing sarcoma. Post-treatment, the tumor showed neural differentiation, a rare finding in Ewing sarcoma cases.
Area of Science:
- Pediatric Oncology
- Skeletal System Neoplasms
- Soft Tissue Tumors
Background:
- Peripheral primitive neuroectodermal tumor/Ewing sarcoma (pPNET/EWS) is a rare malignant tumor.
- Diagnosis typically involves characteristic morphology and genetic translocation t(11;22).
- Treatment usually includes chemotherapy and surgical resection.
Observation:
- An 11-year-old girl presented with a retroperitoneal mass, diagnosed as pPNET/EWS.
- Following chemotherapy and surgery, residual tumor exhibited neuroblastoma-like morphology.
- Genetic analysis confirmed the EWSR1/FLI1 gene fusion in both pre- and post-treatment samples.
Findings:
- The study identified the characteristic t(11;22) translocation and EWSR1/FLI1 gene fusion in both initial and residual tumor specimens.
- The residual tumor displayed neural differentiation, morphologically resembling neuroblastoma.
- This suggests a potential for divergent differentiation within pPNET/EWS under specific conditions.
Implications:
- This case highlights unusual post-treatment differentiation in pPNET/EWS.
- It underscores the importance of comprehensive genetic analysis alongside morphology.
- Further research may elucidate mechanisms driving differentiation in pediatric soft tissue sarcomas.