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Updated: Sep 7, 2025
Establishment of a Primary Culture of Patient-derived Soft Tissue Sarcoma
Published on: April 11, 2018
New molecular entities of soft tissue and bone tumors
Suk Wai Lam1, Tulio M Silva1,2, Judith V M G Bovée1
1Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
Purpose Of Review:
The advances of molecular techniques have led to the refinement of the classification of mesenchymal tumors, leading to newly introduced entities in the recently published fifth edition of the WHO Classification of Soft Tissue and Bone Tumors, which are discussed in this review.
Recent Findings:
For the first time, entities are included of which the name refers to the underlying molecular alteration including round cell sarcoma with EWSR1 -non-ETS fusions, CIC -rearranged sarcoma, and sarcoma with BCOR genetic alteration. EWSR1-SMAD3 -positive fibroblastic tumor and NTRK -rearranged spindle cell neoplasm are provisionally included as 'emerging' entities based on the underlying molecular alteration, though the entity still needs to be better defined. Other newly recognized entities are not named after their molecular change, but the molecular alteration helped to delineate them from others: atypical spindle cell/pleomorphic lipomatous tumor, anastomosing hemangioma, angiofibroma of soft tissue, myxoid pleomorphic liposarcoma, and poorly differentiated chordoma.
Summary:
Classification of mesenchymal tumors is increasingly based on the underlying molecular changes, although this cannot be interpreted separately from clinical, morphological, and immunohistochemical characteristics.
Insights
The latest WHO classification refines mesenchymal tumor diagnosis by incorporating molecular alterations. This review details newly recognized entities, emphasizing the growing role of molecular pathology in tumor classification.
Area of Science:
- Oncology
- Molecular Pathology
- Histopathology
Background:
- Advances in molecular techniques have significantly refined the classification of mesenchymal tumors.
- The fifth edition of the WHO Classification of Soft Tissue and Bone Tumors introduces new entities.
- Molecular alterations are increasingly central to tumor classification.
Purpose of the Study:
- To review the newly introduced entities in the fifth edition of the WHO Classification of Soft Tissue and Bone Tumors.
- To discuss the impact of molecular alterations on the classification of mesenchymal tumors.
- To highlight emerging entities defined by specific genetic changes.
Main Methods:
- Review of recent literature and the fifth edition WHO Classification.
- Analysis of newly defined mesenchymal tumor entities.
- Correlation of molecular findings with clinical, morphological, and immunohistochemical characteristics.
Main Results:
- Introduction of entities named after molecular alterations: round cell sarcoma with EWSR1-non-ETS fusions, CIC-rearranged sarcoma, and sarcoma with BCOR genetic alteration.
- Provisional inclusion of EWSR1-SMAD3-positive fibroblastic tumor and NTRK-rearranged spindle cell neoplasm as emerging entities.
- Recognition of other entities delineated by molecular alterations, including atypical spindle cell/pleomorphic lipomatous tumor and myxoid pleomorphic liposarcoma.
Conclusions:
- Mesenchymal tumor classification is increasingly driven by underlying molecular changes.
- Molecular data must be integrated with clinical, morphological, and immunohistochemical findings for accurate diagnosis.
- The evolving classification reflects a deeper understanding of tumor biology and genetics.
