WHO classification of tumors of soft tissue

Last revised by Dr Daniel J Bell on 14 Oct 2021

The World Health Organization (WHO) classification of soft tissue tumors is the most widely used pathologic classification system for such disorders. The current revision, part of the 5th edition of the WHO series, was published in 2020 and is reflected in the article below 1.


Adipocytic tumors
Fibroblastic/myofibroblastic tumors
So-called fibrohistiocytic tumors
Vascular tumors
Pericytic (perivascular) tumors
Smooth muscle tumors
Skeletal-muscle tumors
Gastrointestinal stromal tumors
Chondro-osseous tumors
Peripheral nerve sheath tumors
Tumors of uncertain differentiation

Changes from the prior version

New entities and variants

Newly introduced entities include the following 1-5:

  • adipocytic tumors
    • atypical spindle cell/pleomorphic lipomatous tumor
    • myxoid pleomorphic liposarcoma
  • fibroblastic and myofibroblastic tumors
    • angiofibroma of soft tissue
    • superficial CD34-positive fibroblastic tumor
    • EWSR-SMAD3-positive fibroblastic tumor
  • vascular tumors
    • epithelioid hemangioendothelioma features two newly recognized subtypes
    • anastomosing hemangioma
    • tufted angioma and Kaposiform hemangioendothelioma are classified together
  • pericytic (perivascular) tumors
    • myopericytoma, including myofibroma - new subtype: cellular myofibroma/myopericytoma
  • smooth muscle tumors
    • EBV-associated smooth muscle tumor
    • inflammatory leiomyosarcoma
  • skeletal muscle tumors
  • tumors of uncertain differentiation
    • NTRK-rearranged soft tissue neoplasms
Other changes
  • melanotic schwannoma: now renamed to malignant melanotic nerve sheath tumor
  • dedifferentiated liposarcoma: adverse prognostic impact of myogenic and rhabdomyoblastic differentiation as well of a high grade on the FNCLCC (French Federation of Cancer Centers Sarcoma Group) grading system
  • solitary fibrous tumor: 'extrapleural' has been removed

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