Extraskeletal Osteosarcoma

Alternative diagnostic terms
Extraosseous Osteosarcoma
Soft Tissue Osteosarcoma

Common anatomical locations
Deep-soft tissue masses of the extremities.

Pathology comment
No connection to the skeletal system; identification of neoplastic bone/osteoid in association with malignant cells in otherwise unclassified soft tissue sarcoma.

Source
Oda Y, Yamashita K, Hameed M. Extraskeletal osteoSarcoma. In: WHO Classification of Tumors Editorial Board. Soft tissue and bone tumors [Internet]. Lyon (France): International Agency for Research on Cancer; 2020 [2024 Dec 29]. (WHO Classification of Tumors Series, 5th ed.; vol. 3). Available from: https://tumourclassification.iarc.who.int/login?redirecturl=%2Fchapters%2F33.

For diagnosis or treatment
Any center listed as a SARC Honor Roll member in the Sarcoma Centers Directory »

Patient advocacy
Any organization with an established program for patient triage, support, and education. See Patient Support Organizations »

Clinical trials
SARC Clinical Trial – SARC032-SU2C Soft Tissue Sarcoma of the Extremity
SARC Clinical Trial – SARC038 Osteosarcoma

Find other clinical studies registered on ClinicalTrials.gov

Alternative diagnostic terms
Undifferentiated Small Round Cell Sarcomas

Common anatomical locations
Ewing Sarcoma is the second most common primary bone tumor, second to pediatric osteosarcoma. Soft tissue Ewing’s occurs in approximately 10-15% of Ewing’s patients, with a broad range of anatomic “primary” sites, including the chest, pelvis, extremities, paraspinal soft tissues, and retroperitoneal/abdominal soft tissues. Patients over the age of 30 years are less likely to have an Ewing Sarcoma but are more likely to have a soft tissue Ewing tumor.

Pathology comment
Askin’s tumor is a primitive neuroectodermal tumor separate from Ewing that typically involves the chest wall. Other round cell sarcomas, distinguished from Ewing tumors, include CIC rearranged sarcomas and sarcomas with BCOR genetic alterations. Ewing sarcoma is classified as an undifferentiated small round cell sarcoma and is distinguished by the FET-ETC fusion genes, which code for transcription factors that regulate many genes. Ewing histology usually reveals a uniform small round cell morphology that is strongly positive for CD-99 (cell surface glycoprotein) in 95% of patients. Most Ewing’s patients (85%) are diagnosed with a (t(11,22)(q24q12) translocation, resulting in an EWSR1-FlI1 fusion transcript.  

Current survival for nonmetastatic Ewing in pediatric patients treated with systemic therapy and resection (with or without Radiation therapy) is approximately 65-70% at 5 years. Pelvic and spinal primary tumor locations are associated with lower patient survival, while higher survival is associated with a good response to initial, preoperative chemotherapy, which is best monitored by serial preoperative  Flourodeoxyglucose PET scan evaluation.

Source
Grunewald TGP, Cidre-Aranaz F, Surdez D, et al. Ewing sarcoma. NatRev Dis Primers.2018 Jul 5 ,4 (1):5 PMID: 29977059

For diagnosis or treatment
Any center listed as a SARC Honor Roll member in the Sarcoma Centers Directory »

Patient advocacy
Any organization with an established program for patient triage, support, and education. See Patient Support Organizations »

Clinical trials
SARC Clinical Trial – SARC037 Ewing Sarcoma

Find other clinical studies registered on ClinicalTrials.gov

Alternative diagnostic terms
NR4A3-rearranged Myxoid Sarcoma (provisional) (acceptable)

Common anatomical locations
None

Pathology comment
Characterized by NR4A3 gene rearrangement. There is no evidence of cartilaginous differentiation despite the name.

Source
Fletcher CDM, Horvai AE, Lucas DR, Agaram NP. Extraskeletal myxoid chondrosarcoma. In: WHO Classification of Tumors Editorial Board. Soft tissue and bone tumors [Internet]. Lyon (France): International Agency for Research on Cancer; 2020 [2024 Dec 29]. (WHO Classification of Tumors Series, 5th ed.; vol. 3). Available from: https://tumourclassification.iarc.who.int/login?redirecturl=%2Fchapters%2F33

For diagnosis or treatment
Any center listed in the Sarcoma Centers Directory »

Patient advocacy
Any organization with an established program for patient triage, support, and education. See Patient Support Organizations »

Clinical trials
SARC Clinical Trials – None
Find other clinical studies registered on ClinicalTrials.gov

Alternative diagnostic terms
Pending

Common anatomical locations
Pending

Pathology comment
Pending

Source
Pending

For diagnosis or treatment
Any center listed in the Sarcoma Center Directory »

Patient advocacy
Any organization with an established program for patient triage, support, and education. See Patient Support Organizations »

Clinical trials
SARC Clinical Trials – None
Find other clinical studies registered on ClinicalTrials.gov