Fusion-positive soft tissue tumors: A selective review.

Area of Science:

• Oncology
• Pathology
• Genetics

Background:

• Soft tissue tumor diagnosis is challenging due to rarity and diversity.
• Molecular genetics, particularly gene fusions, has advanced understanding of pathogenesis.
• Characteristic gene fusions offer diagnostic potential for rare lesions.

Purpose of the Study:

• To review four fusion-driven soft tissue tumors illustrating evolving diagnostic insights.
• To highlight the importance of molecular genetic findings in classifying these tumors.
• To emphasize integrating molecular data with clinicopathological information.

Main Methods:

• Review of literature on fusion-driven soft tissue tumors.
• Focus on specific examples: NUTM1-rearranged sarcoma, SRF-rearranged myoid neoplasm, superficial FET-ETS neurocristic tumor, and EWSR1::WT1-fused glomoid/myoid neoplasms.
• Analysis of molecular genetic characteristics and their diagnostic implications.

Main Results:

• NUTM1-rearranged sarcoma: a novel entity defined by molecular genetics.
• SRF-rearranged myoid neoplasm: clarifies pediatric "leiomyosarcoma" understanding.
• Superficial FET-ETS neurocristic tumor: benign entity with fusions similar to Ewing sarcoma.
• Glomoid/myoid neoplasms: distinct group with EWSR1::WT1 fusions.

Conclusions:

• Fusion-driven soft tissue tumors represent a complex and evolving diagnostic area.
• Molecular genetic testing is essential for accurate diagnosis and classification.
• Integrated approach combining molecular data with clinicopathological features is critical.