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Childhood Soft Tissue Sarcoma Treatment (PDQ®)

Health Professional Version

Histopathological Classification

World Health Organization (WHO) Classification of Soft Tissue Sarcomas (STSs)

The WHO lists the following cell types in its classification of STSs:[1,2]

This summary focuses on high-grade sarcomas and low-grade tumors that present special problems in the pediatric and adolescent population, including desmoid tumor and infantile fibrosarcoma. For many low-grade STSs, surgical resection is curative and there is no need for additional therapy.

  • Adipocytic tumors.
    • Liposarcoma—myxoid or well-differentiated.
  • Chondro-osseous tumors.
    • Extraskeletal chondrosarcoma (mesenchymal and other variants).[3]
    • Extraskeletal osteosarcoma.
  • Fibroblastic/myofibroblastic tumors.
    • Desmoid tumor (also called aggressive fibromatosis).a
    • Fibrosarcoma.b[4]
    • Inflammatory myofibroblastic tumor.a
    • Low-grade fibromyxoid sarcoma.[5]
    • Myxofibrosarcoma, low grade.
    • Sclerosing epithelioid fibrosarcoma.
  • Skeletal muscle tumors.
  • Smooth muscle tumors.
    • Leiomyosarcoma.
  • So-called fibrohistiocytic tumors.
    • Plexiform fibrohistiocytic tumor.a
    • Undifferentiated pleomorphic sarcoma/malignant fibrous histiocytoma (including pleomorphic, giant cell, myxoid/high-grade myxofibrosarcoma, and inflammatory forms).
  • Tumors of peripheral nerves.
    • Malignant peripheral nerve sheath tumor.
  • Tumors of uncertain differentiation.
    • Alveolar soft part sarcoma.
    • Clear cell sarcoma of soft tissue.
    • Desmoplastic small round cell tumor.[6]
    • Epithelioid sarcoma.
    • Extrarenal rhabdoid tumor.
    • Extraskeletal myxoid chondrosarcoma.
    • Primitive neuroectodermal tumor (PNET)/extraskeletal Ewing tumor.
    • Synovial sarcoma.
    • Undifferentiated sarcoma; sarcoma, not otherwise specified (NOS).[7]
  • Vascular tumors.
    • Angiosarcoma, deep.c
    • Epithelioid hemangioendothelioma.
    • Hemangiopericytoma (infantile).

[Note: aNot a high-grade tumor; bThe category of fibrosarcoma can be inclusive of fibrosarcomatous differentiation in dermatofibrosarcoma protuberans; cCutaneous angiosarcoma may be difficult to stage using the American Joint Committee on Cancer system.]


  1. Soft tissue sarcoma. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 291-6.
  2. Brodowicz T, Schwameis E, Widder J, et al.: Intensified Adjuvant IFADIC Chemotherapy for Adult Soft Tissue Sarcoma: A Prospective Randomized Feasibility Trial. Sarcoma 4 (4): 151-60, 2000. [PUBMED Abstract]
  3. Dantonello TM, Int-Veen C, Leuschner I, et al.: Mesenchymal chondrosarcoma of soft tissues and bone in children, adolescents, and young adults: experiences of the CWS and COSS study groups. Cancer 112 (11): 2424-31, 2008. [PUBMED Abstract]
  4. Steelman C, Katzenstein H, Parham D, et al.: Unusual presentation of congenital infantile fibrosarcoma in seven infants with molecular-genetic analysis. Fetal Pediatr Pathol 30 (5): 329-37, 2011. [PUBMED Abstract]
  5. Evans HL: Low-grade fibromyxoid sarcoma: a clinicopathologic study of 33 cases with long-term follow-up. Am J Surg Pathol 35 (10): 1450-62, 2011. [PUBMED Abstract]
  6. Barnoud R, Sabourin JC, Pasquier D, et al.: Immunohistochemical expression of WT1 by desmoplastic small round cell tumor: a comparative study with other small round cell tumors. Am J Surg Pathol 24 (6): 830-6, 2000. [PUBMED Abstract]
  7. Alaggio R, Collini P, Randall RL, et al.: Undifferentiated high-grade pleomorphic sarcomas in children: a clinicopathologic study of 10 cases and review of literature. Pediatr Dev Pathol 13 (3): 209-17, 2010 May-Jun. [PUBMED Abstract]
  • Updated: January 29, 2015