Abstract
Improved understanding of tumor biology through molecular alteration and genetic advances has resulted in a number of major changes in the 2020 World Health Organization’s (WHO) classification of bone tumors. These changes include the reclassification of the existing tumors and the introduction of several new entities. A new chapter on undifferentiated small round cell sarcomas of bone and soft tissue was added to classify Ewing sarcoma and the family of Ewing-like sarcomas, which share similar histologies but different molecular and clinical behaviors. Knowledge of the current classification of bone tumors is essential to ensure the appropriate recognition of the inherent biological potential of individual osseous lesions for optimal treatment, follow-up, and overall outcome. This article reviews the major changes to the 2020 WHO’s classification of primary bone tumors and the pertinent imaging of selected tumors to highlight these changes.
Similar content being viewed by others
References
The WHO Classification of Tumours Editorial Board. WHO classification of tumours soft tissue and bone tumours. 5th ed. Lyon: IARC Press; 2020.
Choi JH, Ro JY. The 2020 WHO classification of tumors of bone: an updated review. Adv Anat Pathol. 2021;28(3):119–38. https://doi.org/10.1097/PAP.0000000000000293.
Flanagan AM, Blay JY, Bovée JVMG, Bredella A, Cool P, Nielsen GP, Yoshida A. 2020 Bone tumours: introduction. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:340–344.
Xu H, Nugent D, Monforte HL, Binitie OT, Ding Y, Letson GD, et al. Chondroblastoma of bone in the extremities: a multicenter retrospective study. J Bone Joint Surg Am. 2015;97(11):925–31. https://doi.org/10.2106/JBJS.N.00992.
Hogendoorn PCW, Bloem JL, Bridge JA. Chondromyxoid fibroma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:362–364.
Bhamra JS, Al-Khateeb H, Dhinsa BS, Gikas PD, Tirabosco R, Pollock RC, et al. Chondromyxoid fibroma management: a single institution experience of 22 cases. World J Surg Oncol. 2014;12(12):283. https://doi.org/10.1186/1477-7819-12-283.
Flanagan AM, Bloem JL, Cates JMM, O’Donnell PG. Synovial Chondromatosis. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:368–369.
Houdek MT, Wyles CC, Rose PS, Stuart MJ, Sim FH, Taunton MJ. High rate of local recurrence and complications following total knee arthroplasty in the setting of synovial chondromatosis. J Arthroplasty. 2017;32(7):2147–50. https://doi.org/10.1016/j.arth.2017.02.040.
Tibbo ME, Wyles CC, Rose PS, Sim FH, Houdek MT, Taunton MJ. Long-term outcome of hip arthroplasty in the setting of synovial chondromatosis. J Arthroplasty. 2018 Jul;33(7):2173–6. https://doi.org/10.1016/j.arth.2018.02.027.
Evans S, Boffano M, Chaudhry S, Jeys L, Grimer R. Synovial chondrosarcoma arising in synovial chondromatosis. Sarcoma. 2014;2014:647939. https://doi.org/10.1155/2014/647939.
Murphey MD, Vidal JA, Fanburg-Smith JC, Gajewski DA. Imaging of synovial chondromatosis with radiologic-pathologic correlation. Radiographics. 2007;27(5):1465–88. https://doi.org/10.1148/rg.275075116.
Bovée JVMG, Bloem JL, Flanagan AM, Nielsen GP, Yoshida A. Enchondroma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:353–355.
Brien EW, Mirra JM, Kerr R. Benign and malignant cartilage tumors of bone and joint: their anatomic and theoretical basis with an emphasis on radiology, pathology, and clinical biology I The intramedullary cartilage tumors. Skeletal Radiol. 1997;26(6):325–53. https://doi.org/10.1007/s002560050246.
Brien EW, Mirra JM, Luck JV Jr. Benign and malignant cartilage tumors of bone and joint: their anatomic and theoretical basis with an emphasis on radiology, pathology, and clinical biology. II Juxtacortical cartilage tumors Skeletal Radiol. 1999;28(1):1–20. https://doi.org/10.1007/s002560050466.
Stomp W, Reijnierse M, Kloppenburg M, de Mutsert R, Bovée JV, den Heijer M, NEO study group, et al. Prevalence of cartilaginous tumours as an incidental finding on MRI of the knee. Eur Radiol. 2015;25(12):3480–7. https://doi.org/10.1007/s00330-015-3764-6.
Davies AM, Patel A, Azzopardi C, James SL, Botchu R. Prevalence of Enchondromas of the Proximal Femur in Adults as an Incidental Finding on MRI of the Pelvis. Indian J Radiol Imaging. 2021;31(3):582–5. https://doi.org/10.1055/s-0041-1735915.
Hong ED, Carrino JA, Weber KL, Fayad LM. Prevalence of shoulder enchondromas on routine MR imaging. Clin Imaging. 2011;35(5):378–84. https://doi.org/10.1016/j.clinimag.2010.10.012.
Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I Benign lesions Skeletal Radiol. 2012;41(10):1195–212. https://doi.org/10.1007/s00256-012-1427-0.
Bovée JVMG, Bloem JL, Flanagan AM, Nielsen GP, Yoshida A. Central atypical cartilaginous tumour/chondrosarcoma grade 1. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:370–372.
Eefting D, Schrage YM, Geirnaerdt MJ, Le Cessie S, Taminiau AH, Bovée JV, et al. EuroBoNeT consortium. Assessment of interobserver variability and histologic parameters to improve reliability in classification and grading of central cartilaginous tumors. Am J Surg Pathol. 2009;33(1):50–7. https://doi.org/10.1097/PAS.0b013e31817eec2b.
Zamora T, Urrutia J, Schweitzer D, Amenabar PP, Botello E. Do orthopaedic oncologists agree on the diagnosis and treatment of cartilage tumors of the appendicular skeleton? Clin Orthop Relat Res. 2017;475(9):2176–86. https://doi.org/10.1007/s11999-017-5276-y.
Deckers C, Rooy JWJ, Flucke U, Schreuder HWB, Dierselhuis EF, Geest ICMV. Midterm MRI follow-up of untreated enchondroma and atypical cartilaginous tumors in the long bones. Cancers (Basel). 2021;13(16):4093. https://doi.org/10.3390/cancers13164093.
Davies AM, Patel A, Botchu R, Azzopardi C, James S, Jeys L. The changing face of central chondrosarcoma of bone. One UK-based orthopaedic oncology unit’s experience of 33 years referrals. J Clin Orthop Trauma. 2021;17:106–11. https://doi.org/10.1016/j.jcot.2021.02.017.
van PraagVeroniek VM, Rueten-Budde AJ, Ho V, Dijkstra PDS, Fiocco M, van de Sande MAJ, Study group bone and soft tissue tumours (WeBot). Incidence, outcomes and prognostic factors during 25 years of treatment of chondrosarcomas. Surg Oncol. 2018;27(3):402–8. https://doi.org/10.1016/j.suronc.2018.05.009.
Omlor GW, Lohnherr V, Lange J, Gantz S, Mechtersheimer G, Merle C, et al. Outcome of conservative and surgical treatment of enchondromas and atypical cartilaginous tumors of the long bones: retrospective analysis of 228 patients. BMC Musculoskelet Disord. 2019;20(1):134. https://doi.org/10.1186/s12891-019-2502-7.
Geirnaerdt MJ, Hermans J, Bloem JL, Kroon HM, Pope TL, Taminiau AH, et al. Usefulness of radiography in differentiating enchondroma from central grade 1 chondrosarcoma. AJR Am J Roentgenol. 1997;169(4):1097–104. https://doi.org/10.2214/ajr.169.4.9308471.
Murphey MD, Walker EA, Wilson AJ, Kransdorf MJ, Temple HT, Gannon FH. From the archives of the AFIP: imaging of primary chondrosarcoma: radiologic-pathologic correlation. Radiographics. 2003;23(5):1245–78. https://doi.org/10.1148/rg.235035134.
Douis H, Parry M, Vaiyapuri S, Davies AM. What are the differentiating clinical and MRI-features of enchondromas from low-grade chondrosarcomas? Eur Radiol. 2018;28(1):398–409. https://doi.org/10.1007/s00330-017-4947-0.
Sharif B, Lindsay D, Saifuddin A. The role of imaging in differentiating low-grade and high-grade central chondral tumours. Eur J Radiol. 2021;137:109579. https://doi.org/10.1016/j.ejrad.2021.109579.
Deckers C, Steyvers MJ, Hannink G, Schreuder HWB, de Rooy JWJ, Van Der Geest ICM. Can MRI differentiate between atypical cartilaginous tumors and high-grade chondrosarcoma? A systematic review Acta Orthop. 2020;91(4):471–8. https://doi.org/10.1080/17453674.2020.1763717.
Alhumaid SM, Alharbi A 4th, Aljubair H. Magnetic resonance imaging role in the differentiation between atypical cartilaginous tumors and high-grade chondrosarcoma: an updated systematic review. Cureus. 2020;12(10):e11237. https://doi.org/10.7759/cureus.11237.
Bovée JVMG, Bloem JL, Flanagan AM, Nielsen GP, Yoshida A. Secondary peripheral atypical cartilaginous tumour/chondrosarcoma grade 1. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:373–374.
Bernard SA, Murphey MD, Flemming DJ, Kransdorf MJ. Improved differentiation of benign osteochondromas from secondary chondrosarcomas with standardized measurement of cartilage cap at CT and MR imaging. Radiology. 2010;255(3):857–65. https://doi.org/10.1148/radiol.10082120.
Amary F, Bredella MA, Horvai AE, Mahar AM. Osteoid osteoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:394–396.
Amary F, Bredella MA, Horvai AE, Mahar AM. Osteoblastoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:397–399.
Chai JW, Hong SH, Choi JY, Koh YH, Lee JW, Choi JA, Kang HS. Radiologic diagnosis of osteoid osteoma: from simple to challenging findings. Radiographics. 2010 May;30(3):737-49. https://doi.org/10.1148/rg.303095120. Erratum in: Radiographics. 2010 Jul-Aug;30(4):1156 https://doi.org/10.1148/rg.303095120
Jaffe HL. Osteoid-osteoma. Proc R Soc Med. 1953;46(12):1007–12.
Liu J, Han S, Li J, Yuan Y, Guo W, Yuan H. Spinal osteoblastoma: a retrospective study of 35 patients’ imaging findings with an emphasis on MRI. Insights Imaging. 2020;11(1):122. https://doi.org/10.1186/s13244-020-00934-y.
Baumhoer D, Böhling TO, Cates JMM, Cleton-Jansen AM, Hogendoorn PCW, O’Donnell PG, Rosenberg AE. Osteosarcoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:403–409.
Smeland S, Bielack SS, Whelan J, Bernstein M, Hogendoorn P, Krailo MD, et al. Survival and prognosis with osteosarcoma: outcomes in more than 2000 patients in the EURAMOS-1 (European and American Osteosarcoma Study) cohort. Eur J Cancer. 2019;109:36–50. https://doi.org/10.1016/j.ejca.2018.11.027.
Flanagan AM, Bridge JA, O’Donnell PG. Secondary osteosarcoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:419–421.
Suurmeijer AJH, Cleton-Jansen AM. Desmoplastic fibroma of bone. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:422–423.
Berkeley R, Andrei V, Saifuddin A. The rare primary bone sarcomas: imaging pathological correlation. Skeletal Radiol. 2021;50(8):1491–511. https://doi.org/10.1007/s00256-020-03692-6.
Dei Tos AP, Czerniak B, Inwards CY. Fibrosarcoma of bone. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:424–425.
Errani C, Vanel D, Gambarotti M, Alberghini M, Picci P, Faldini C. Vascular bone tumors: a proposal of a classification based on clinicopathological, radiographic and genetic features. Skeletal Radiol. 2012;41(12):1495–507. https://doi.org/10.1007/s00256-012-1510-6.
Bovée JVMG, Rosenberg AE. Epitheliod haemangioma of bone. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:428–430.
Zhou Q, Lu L, Fu Y, Xiang K, Xu L. Epithelioid hemangioma of bone: a report of two special cases and a literature review. Skeletal Radiol. 2016;45(12):1723–7. https://doi.org/10.1007/s00256-016-2482-8.
Tsuda Y, Suurmeijer AJH, Sung YS, Zhang L, Healey JH, Antonescu CR. Epithelioid hemangioma of bone harboring FOS and FOSB gene rearrangements: A clinicopathologic and molecular study. Genes Chromosomes Cancer. 2021;60(1):17–25. https://doi.org/10.1002/gcc.22898.
Agaram NP, Bredella MA. Aneurysmal bone cyst. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:437–439.
Flanagan AM, Larousserie F,O’Donnell PG, Yoshida A. Giant cell tumour of bone. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:440–446.
Tahir I, Andrei V, Pollock R, Saifuddin A. Malignant giant cell tumour of bone: a review of clinical, pathological, and imaging features. Skeletal Radiol. 2021. https://doi.org/10.1007/s00256-021-03913-6.
Liu W, Chan CM, Gong L, Bui MM, Han G, Letson GD, et al. Malignancy in giant cell tumor of bone in the extremities. J Bone Oncol. 2020 Nov;5(26):100334. https://doi.org/10.1016/j.jbo.2020.100334.
Tirabosco R, O’Donnell PG, Yamaguchi T. Conventional chordoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:451–453.
Tirabosco R, Hameed M. Dedifferentiated chordoma. In: Lokuhetty D, White V, Cree I, editors. WHO classification of tumours, soft tissue and bone tumors. 5th ed. International Agency for Research on Cancer (IARC): Lyon Cedex, France; 2020. p. 454–5.
Nielsen GP, Dickson BC, Tirabosco R. Poorly differentiated chordoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:456–457.
Shih AR, Cote GM, Chebib I, Choy E, DeLaney T, Deshpande V, et al. Clinicopathologic characteristics of poorly differentiated chordoma. Mod Pathol. 2018;31(8):1237–45. https://doi.org/10.1038/s41379-018-0002-1.
Rekhi B, Michal M, Ergen FB, Roy P, Puls F, Haugland HK, et al. Poorly differentiated chordoma showing loss of SMARCB1/INI1: Clinicopathological and radiological spectrum of nine cases, including uncommon features of a relatively under-recognized entity. Ann Diagn Pathol. 2021;55:151809. https://doi.org/10.1016/j.anndiagpath.2021.151809.
Olson JT, Wenger DE, Rose PS, Petersen IA, Broski SM. Chordoma: 18F-FDG PET/CT and MRI imaging features. Skeletal Radiol. 2021;50(8):1657–66. https://doi.org/10.1007/s00256-021-03723-w.
Gambarotti M, Inwards CY. Fibrocartilaginous mesenchymoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:470–471.
Gambarotti M, Righi A, Vanel D, Cocchi S, Benini S, Elli FM, et al. Fibrocartilaginous mesenchymoma of bone: a single-institution experience with molecular investigations and a review of the literature. Histopathology. 2017;71(1):134–42. https://doi.org/10.1111/his.13201.
Rosenberg AE, Bloem JL, Sumathi VP. Lipoma and hibernoma of bone. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:475–477.
Bonar SF, Watson G, Gragnaniello C, Seex K, Magnussen J, Earwaker J. Intraosseous hibernoma: characterization of five cases and literature review. Skeletal Radiol. 2014;43(7):939–46. https://doi.org/10.1007/s00256-014-1868-8.
Myslicki FA, Rosenberg AE, Chaitowitz I, Subhawong TK. Intraosseous Hibernoma: Five Cases and a Review of the Literature. J Comput Assist Tomogr. 2019;43(5):793–8. https://doi.org/10.1097/RCT.0000000000000912.
Gitto S, Doeleman T, van de Sande MAJ, van Langevelde K. Intraosseous hibernoma of the appendicular skeleton. Skeletal Radiol. 2021. https://doi.org/10.1007/s00256-021-03956-9.
Nielsen GP, Hogendoorn PCW. Adamantinoma of long bones. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:463–465.
Rekhi B, Sahay A, Puri A. Clinicopathologic Features of Two Rare Cases of Dedifferentiated Adamantinomas, Including Diagnostic Implications. Int J Surg Pathol. 2019;27(2):193–202. https://doi.org/10.1177/1066896918790388.
Sharifai N, Runyon R, Friedman M, Cipriano C, Chrisinger. Adamantinoma of the Femur with High-Grade Epithelial and Sarcomatoid Components: Case Report and Review of the Literature. AJSP Reviews & Reports. 2020;25(1):19–25. https://doi.org/10.1097/PCR.0000000000000359.
Bethapudi S, Ritchie DA, Macduff E, Straiton J. Imaging in osteofibrous dysplasia, osteofibrous dysplasia-like adamantinoma, and classic adamantinoma. Clin Radiol. 2014;69(2):200–8. https://doi.org/10.1016/j.crad.2013.09.011 (Epub 2013Nov 5).
Khanna M, Delaney D, Tirabosco R, Saifuddin A. Osteofibrous dysplasia, osteofibrous dysplasia-like adamantinoma and adamantinoma: correlation of radiological imaging features with surgical histology and assessment of the use of radiology in contributing to needle biopsy diagnosis. Skeletal Radiol. 2008;37(12):1077–84. https://doi.org/10.1007/s00256-008-0553-1.
Scholfield DW, Sadozai Z, Ghali C, Sumathi V, Douis H, Gaston L, et al. Does osteofibrous dysplasia progress to adamantinoma and how should they be treated? Bone Joint J. 2017;99-B(3):409–16. https://doi.org/10.1302/0301-620X.99B3.38050.
Inwards CY, Czerniak B, Dei, Tos AP. Undifferentiated pleomorphic sarcoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:480–482.
Gulati N, Allen CE. Langerhans cell histiocytosis: Version 2021. Hematol Oncol. 2021;39(Suppl 1):15–23. https://doi.org/10.1002/hon.2857.
Pileri SA, Cheuk W, Picarsic J. Langerhans cell histiocytosis. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:492–494
Rajakulasingam R, Siddiqui M, Michelagnoli M, Saifuddin A. Skeletal staging in Langerhans cell histiocytosis: a multimodality imaging review. Skeletal Radiol. 2021;50(6):1081–93. https://doi.org/10.1007/s00256-020-03670-y.
Azouz EM, Saigal G, Rodriguez MM, Podda A. Langerhans’ cell histiocytosis: pathology, imaging, and treatment of skeletal involvement. Pediatr Radiol. 2005;35(2):103–15. https://doi.org/10.1007/s00247-004-1262-0.
Emile JF, Haroche J, Picarsic J, Tirabosco R. Erdheim-Chester disease. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:495–497.
Choraria A, Andrei V, Rajakulasingam R, Saifuddin A. Musculoskeletal imaging features of non-Langerhans cell histiocytoses. Skeletal Radiol. 2021;50(10):1921–40. https://doi.org/10.1007/s00256-021-03765-0.
Emile JF, Cohen-Aubart F, Collin M, Fraitag S, Idbaih A, Abdel-Wahab O, et al. Histiocytosis Lancet. 2021;398(10295):157–70. https://doi.org/10.1016/S0140-6736(21)00311-1.
Rosenberg AE, Demicco EG. Rosai-Dorfman disease. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:498–499.
Garcia RA, DiCarlo EF. Rosai-Dorfman Disease of Bone and Soft Tissue. Arch Pathol Lab Med. 2022;146(1):40–6. https://doi.org/10.5858/arpa.2021-0116-RA.
de Álava E, Lessnick SL, Stamenkovic I. Ewing sarcoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:323–325.
Antonescu CR, Yoshida A. CIC-rearranged sarcoma. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:330–332.
Antonescu CR, Puls F, Tirode F. Sarcoma with BCOR genetic alterations. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:333–335.
Le Loarer F, Szuhai K, Tirode F. Round cell sarcoma with EWSR1–non-ETS fusions. In: Lokuhetty D, White V, Cree I, eds. WHO classification of tumours, soft tissue and bone tumors. 5th ed. Lyon Cedex, France: International Agency for Research on Cancer (IARC); 2020:326–329.
Kallen ME, Hornick JL. From the ashes of “Ewing-like” sarcoma: A contemporary update of the classification, immunohistochemistry, and molecular genetics of round cell sarcomas. Semin Diagn Pathol. 2022;39(1):29–37. https://doi.org/10.1053/j.semdp.2021.10.002.
Brady EJ, Hameed M, Tap WD, Hwang S. Imaging features and clinical course of undifferentiated round cell sarcomas with CIC-DUX4 and BCOR-CCNB3translocations. Skeletal Radiol. 2021;50(3):521–9. https://doi.org/10.1007/s00256-020-03589-4.
Sirisena UDN, Rajakulasingam R, Saifuddin A. Imaging of bone and soft tissue BCOR-rearranged sarcoma. Skeletal Radiol. 2021;50(7):1291–301. https://doi.org/10.1007/s00256-020-03683-7.
Funding
National Cancer Center,P30 CA008748
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Key points
• Chondroblastoma, chondromyxoid fibroma, and aneurysmal bone cyst are classified as benign. Osteofibrous dysplasia-like adamantinoma and synovial chondromatosis are now categorized as intermediate (locally aggressive).
• The designation of atypical cartilaginous tumors is reserved for the appendicular skeleton and the histologically identical locally aggressive hyaline cartilage tumor is termed chondrosarcoma grade 1 in the axial skeleton and flat bones.
• Erdheim-Chester Erdheim-Chester disease is no longer considered an intermediate locally aggressive tumor due to its unfavorable clinical outcomes by its multiorgan involvement and is now classified as a hematopoietic neoplasm of bone.
• Ewing sarcoma is no longer classified as a bone tumor and is now addressed in a new category, titled “undifferentiated small round cell sarcomas of bone and soft tissue.”
Rights and permissions
About this article
Cite this article
Hwang, S., Hameed, M. & Kransdorf, M. The 2020 World Health Organization classification of bone tumors: what radiologists should know. Skeletal Radiol 52, 329–348 (2023). https://doi.org/10.1007/s00256-022-04093-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00256-022-04093-7