Soft Tissue Sarcomas
These are other sarcomas that typically occur in soft tissue in adults and can also occur in bone. They include undifferentiated pleomorphic sarcoma (UPS), fibrosarcoma, leiomyosarcoma, and angiosarcoma, among others. While leiomyosarcoma of bone is typically treated with surgery alone, many physicians treat UPS of bone like other osteogenic sarcomas, using chemotherapy and surgery as the main treatments.
Rare Sarcomas* are defined as malignancies that occur with an incidence of greater than one per 1,000,000 per year and represent 80% of all soft tissue sarcomas.
Ultra-Rare Sarcomas** are defined as malignancies with an incidence of less than one per 1,000,000 per year, accounting for 20% of all soft tissue sarcomas and involving 50 ultra-rare soft tissue sarcoma diagnoses.
Rare soft tissue diagnoses include:
- Gastrointestinal Stromal Tumors (GIST)
- Undifferentiated Pleomorphic Sarcoma (UPS)
- Differentiated (Low-Grade) Liposarcoma (WDLPS)
- High-Grade Dedifferentiated Liposarcoma (DDLPS)
- Leiomyosarcoma (LMS)
- Dermatofibrosarcoma Protuberans (DFSP)
- Solitary Fibrous Tumor (SFT)
- Angiosarcoma
- Myxofibrosarcoma
- PVNS and Tenosynovial Giant Cell Tumor
- Myxoid Liposarcoma (MLPS)
Ultra-rare soft tissue sarcomas include:
- Adult Fibrosarcoma
- Alveolar Rhabdomyosarcoma (ARMS)
- Alveolar Soft Part Sarcoma (ASPS)
- Clear Cell Sarcoma (CCS)
- Desmoplastic Small Round Cell Tumor (DSRCT)
- Epithelioid Sarcoma (ES)
- Extraskeletal Soft Tissue Ewing Sarcoma
- Histiocytic Sarcoma
- Inflammatory Myofibroblastic Tumor (IMT)
- Intimal Sarcoma of the Pulmonary Artery
- Glomus Tumor (malignant)
- Extraskeletal Osteosarcoma
- Hemangioendothelioma
- Infantile Fibrosarcoma
- Pleomorphic Liposarcoma
*WHO Classification of Tumors Editorial Board: Soft Tissue and Bone Tumors,” Lyon (France):
International Agency for Research on Cancer; 2020 [March 15, 2021]. (WHO Classification of Tumors Series, 5th ed.; vol. 3).
**Ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society community of experts on the incidence threshold and the list of entities. Cancer. 2021 Aug 15;127(16):2934- 2942. doi: 10.1002/cncr.33618. Epub 2021 Apr 28. PMID: 33910263; PMCID: PMC8319065.