WHO classification of tumors of bone

Changed by Henry Knipe, 23 Mar 2022

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The World Health Organisation (WHO) classification of bone tumours 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.

Classification

Chondrogenic tumours

osteochondroma
periosteal chondroma
enchondroma
chondromyxoid fibroma
osteochondromyxoma
subungual exostosis
bizarre parosteal osteochondromatous proliferation
synovial chondromatosis
chondroblastoma
central atypical cartilaginous tumour/chondrosarcoma (grade 1)
secondary peripheral atypical cartilaginous tumour/ chondrosarcoma (grade 1)
central chondrosarcoma (grades 2-3)
secondary chondrosarcoma (grade 2-3)
periosteal chondrosarcoma
dedifferentiated chondrosarcoma
mesenchymal chondrosarcoma
clear cell chondrosarcoma

Osteogenic tumours

osteoma
osteoid osteoma
osteoblastoma
low-grade central osteosarcoma
osteosarcoma
- conventional osteosarcoma
- telangiectatic osteosarcoma
- small cell osteosacroma
parosteal osteosarcoma
periosteal osteosarcoma
high-grade surface osteosarcoma
secondary osteosarcoma

Fibrogenic tumours

Vascular tumours

Osteoclastic giant cell-rich tumours

Notochordal tumours

Other mesenchymal tumours of bone

Haematopoietic neoplasms

Changes from the prior version

New entities and variants

Newly introduced entities include the following ¹:

chondrogenic tumours
- secondary peripheral atypical cartilaginous tumour/ chondrosarcoma (grade 1)
- secondary chondrosarcoma (grade 2-3)
osteogenic tumours
- secondary osteosarcoma
notochordal tumours
- dedifferentiated chordoma
- poorly differentiated chordoma
other mesenchymal tumours of bone
- fibrocartilaginous mesenchymoma
- bone metastases

Other changes

Ewing sarcoma has been moved to a whole different chapter together with several other new entities of undifferentiated small round cell sarcomas of soft tissue and bone
more clear differentiation of central and secondary peripheral chondrosarcoma variants
central atypical cartilaginous tumour/chondrosarcoma (grade 1)
secondary peripheral atypical cartilaginous tumour/ chondrosarcoma (grade 1)
central chondrosarcoma (grades 2-3)
secondary chondrosarcoma (grade 2-3)
non-ossifying fibroma and aneurysmal bone cyst have been classified as osteoclastic giant cell-rich tumours
Langerhans cell histiocytosis, Erdheim-Chester disease and Rosai-Dorfman disease have been classified as haematopoietic neoplasms of bone
myogenic, lipogenic, epithelial tumours and tumours of undefined neoplastic nature have been classified as other mesenchymal tumours of bone which also includes undifferentiated pleomorphic sarcoma
giant cell lesion of the small bones has been removed as a separate entity

-<a href="/articles/langerhans-cell-histiocytosis-skeletal-manifestations-1">Langerhans cell histiocytosis</a>, <a href="/articles/erdheim-chester-disease">Erdheim-Chester disease</a> and <a href="/articles/rosai-dorfman-disease">Rosai-Dorfman disease</a> have been classified as haematopoietic neoplasms</li>
+<a href="/articles/langerhans-cell-histiocytosis-skeletal-manifestations-1">Langerhans cell histiocytosis</a>, <a href="/articles/erdheim-chester-disease">Erdheim-Chester disease</a> and <a href="/articles/rosai-dorfman-disease">Rosai-Dorfman disease</a> have been classified as haematopoietic neoplasms of bone</li>

References changed:

1. W. H. O. Classification WHO Classification of Tumours Editorial Board, Who Classification of Tumours Editorial. Soft Tissue and Bone Tumours. (2020) ISBN: 9789283245025 - <a href="http://books.google.com/books?vid=ISBN9789283245025">Google Books</a>
2. Christopher D. M. Fletcher. WHO Classification of Tumours of Soft Tissue and Bone. (2013) ISBN: 9789283224341 - <a href="http://books.google.com/books?vid=ISBN9789283224341">Google Books</a>
1. W. H. O. Classification WHO Classification of Tumours Editorial Board, Who Classification of Tumours Editorial. Soft Tissue and Bone Tumours. (2020) ISBN: 9789283245025
2. Christopher D. M. Fletcher. WHO Classification of Tumours of Soft Tissue and Bone. (2013) ISBN: 9789283224341

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