Accurate classification of bone tumors is a critical step in determining an effective treatment plan. The WHO introduced the classification of soft tissue and bone tumors (fifth edition) in 2020.
The new WHO classification of soft tissue and bone tumors, introduced in 2020 (fifth edition), has made significant improvements in classification and introduced many new diagnoses.
The basis for the classification of bone tumors is histopathological.
Bone Tumor Classification
Group | Benign | Intermediate (Local Agressive) | Malignant |
Chondrogenic | Subungual exostosis, Periosteal chondroma, Enchondroma, Osteochondroma, Chondroblastoma vb. | Chondromatosis NOS, Atypical cartilaginous tumor | Chondrosarcoma (G1-3), Periosteal, Clear cell, Mesenchymal, Dedifferentiated |
Osteogenic | Osteoma NOS, Osteoid osteoma NOS | Osteoblastoma NOS | Low-grade central osteosarcoma, Osteosarcoma NOS, Parosteal, Periosteal, High-grade surface, Secondary |
Fibrogenic | — | Desmoplastic fibroma | Fibrosarcoma NOS |
Vascular (Bone) | Hemangioma NOS | Epithelioid hemangioma | Epithelioid hemangioendothelioma NOS, Angiosarcoma |
Osteoclastic Giant Cell-Rich | Aneurysmal bone cyst, Non-ossifying fibroma | Giant cell tumor of bone NOS | Malignant giant cell tumor of bone |
Notochordal | Benign notochordal cell tumor | — | Chordoma NOS (chondroid dahil), Dedifferentiated, Poorly differentiated |
Other Mesenchymal (Bone) | Chondromesenchymal hamartoma, Simple bone cyst, Fibrous dysplasia, Osteofibrous dysplasia, Lipoma, Hibernoma | Osteofibrous dysplasia-like adamantinoma, Mesenchymoma NOS | Adamantinoma (dediff.), Leiomyosarcoma NOS, Pleomorphic sarcoma undiff., Bone metastases |
Hematopoietic | — | — | Plasmacytoma, Hodgkin, Non-Hodgkin lenfomalar, Langerhans histiocytosis, Erdheim-Chester, Rosai-Dorfman |
Undifferentiated Small Round Cell | — | — | Ewing sarcoma, CIC-rearranged, BCOR altered sarcoma |