Editing Bone tumor (section)

==Classification==
[[Image:Giant cell tumor of bone08.JPG|thumb|X-ray of a [[giant cell bone tumor]] in the head of the 4th metacarpal of the left hand. ]]
[[Image:Bonetumor.jpg|thumb|right|An arm bone tumor]]
Bone tumors are traditionally classified as [[benign|noncancerous]] (benign) or [[malignant|cancerous]] (malignant).<ref name=Maruth2018/> Several features of bone tumors and soft tissue tumors overlap.<ref name="Choi2020">{{cite journal | vauthors = Choi JH, Ro JY | title = The 2020 WHO Classification of Tumors of Bone: An Updated Review | journal = Advances in Anatomic Pathology | volume = 28 | issue = 3 | pages = 119–138 | date = May 2021 | pmid = 33480599 | doi = 10.1097/PAP.0000000000000293 | s2cid = 231679037 }}</ref> Their [[WHO blue books|classification]] was revised by the [[World Health Organization]] (WHO) in 2020.<ref name="Anderson2021">{{cite journal | vauthors = Anderson WJ, Doyle LA | title = Updates from the 2020 World Health Organization Classification of Soft Tissue and Bone Tumours | journal = Histopathology | volume = 78 | issue = 5 | pages = 644–657 | date = April 2021 | pmid = 33438273 | doi = 10.1111/his.14265 | s2cid = 231595171 }}</ref> This newer classification categorises bone tumors into [[cartilage tumors]], osteogenic tumors, [[connective tissue|fibrogenic]] tumors, [[blood vessel|vascular]] tumors of bone, osteoclastic giant cell-rich tumors, notochordal tumors, other mesenchymal tumors of bone, and [[blood|hematopoietic]] neoplasms of bone.<ref name=WHOblue2020p.338/><ref name="Choi2020"/>

Bone tumors may be classified as "[[primary tumors]]", which originate in bone or from bone-derived cells and tissues, and "[[secondary tumor]]s" which originate in other sites and spread ([[metastasis|metastasize]]) to the skeleton. [[Carcinoma]]s of the [[Prostate cancer|prostate]], [[Breast cancer|breasts]], [[Lung cancer|lungs]], [[Thyroid cancer|thyroid]], and [[Kidney cancer|kidneys]] are the carcinomas that most commonly metastasize to bone. Secondary malignant bone tumors are estimated to be 50 to 100 times as common as primary bone cancers.<ref>{{Cite web |last=Hussain |first=Dr Shabbir |date=2025-04-12 |title=हड्डी का कैंसर (बोन कैंसर): कारण, लक्षण, निदान और उपचार |url=https://physiotalkofficial.com/bonecancer/ |access-date=2025-05-23 |website=Physio talk official |language=en-US}}</ref>

===Primary bone tumors===
Primary tumors of bone can be divided into [[benign|benign tumors]] and [[cancer]]s. Common benign bone tumors may be [[neoplasia|neoplastic]], developmental, [[Physical trauma|traumatic]], [[infection|infectious]], or [[inflammation|inflammatory]] in etiology. Some benign tumors are not true neoplasms, but rather, represent [[hamartoma]]s, namely the [[osteochondroma]]. The most common locations for many primary tumors, both benign and malignant include the distal femur and proximal tibia (around the knee joint). Examples of benign bone tumors include [[osteoma]], [[osteoid osteoma]], [[osteochondroma]], [[osteoblastoma]], [[enchondroma]], [[giant cell tumor of bone]] and [[aneurysmal bone cyst]].{{citation needed|date=June 2021}}

Malignant primary bone tumors, known as [[bone sarcoma]]s, include [[osteosarcoma]], [[chondrosarcoma]], [[Ewing sarcoma]], [[fibrosarcoma]], and other types. While malignant fibrous histiocytoma (MFH) - now generally called "[[pleomorphic undifferentiated sarcoma]]" - primary in bone is known to occur occasionally,<ref name='JeonSong'>Jeon DG, Song WS, Kong CB, Kim JR, Lee SY. MFH of Bone and Osteosarcoma Show Similar Survival and Chemosensitivity. ''Clin Orthop Rel Res'' 469;584-90.</ref> current paradigms tend to consider MFH a [[wastebasket diagnosis]], and the current trend is toward using specialized studies (i.e. [[Genetics|genetic]] and [[immunohistochemistry|immunohistochemical]] tests) to classify these undifferentiated tumors into other tumor classes. [[Multiple myeloma]] is a [[hematology|hematologic]] cancer, originating in the bone marrow, which also frequently presents as one or more bone lesions.<ref>{{cite web|url= https://www.lecturio.com/concepts/multiple-myeloma/|title= Multiple Myeloma|website= The Lecturio Medical Concept Library|access-date= 26 August 2021|archive-date= 26 July 2024|archive-url= https://web.archive.org/web/20240726175145/https://www.lecturio.com/concepts/multiple-myeloma/|url-status= live}}</ref>

[[Germ cell tumors]], including [[teratoma]], often present and originate in the midline of the sacrum, coccyx, or both. These sacrococcygeal teratomas are often relatively amenable to treatment.<ref>{{cite journal | vauthors = Maoz A, Matsuo K, Ciccone MA, Matsuzaki S, Klar M, Roman LD, Sood AK, Gershenson DM | display-authors = 6 | title = Molecular Pathways and Targeted Therapies for Malignant Ovarian Germ Cell Tumors and Sex Cord-Stromal Tumors: A Contemporary Review | journal = Cancers | volume = 12 | issue = 6 | page = 1398 | date = May 2020 | pmid = 32485873 | pmc = 7353025 | doi = 10.3390/cancers12061398 | doi-access = free }}</ref>

===Secondary bone tumors===
Secondary bone tumors are [[metastasis|metastatic]] [[lesion]]s which have spread from other organs, most commonly carcinomas of the breast, lung, and prostate. Rarely, primary bone malignancies such as [[osteosarcoma]] may also spread to other bones.<ref>{{cite web|url= https://www.lecturio.com/concepts/osteosarcoma/|title= Osteosarcoma|website= The Lecturio Medical Concept Library|access-date= 26 August 2021|archive-date= 25 August 2021|archive-url= https://web.archive.org/web/20210825062514/https://www.lecturio.com/concepts/osteosarcoma/|url-status= live}}</ref>
Reliable and valid statistics on the incidence, prevalence, and mortality of malignant bone tumours are difficult to come by, particularly in older adults (those over 75 years of age) - because [[carcinomas]] that are widely metastatic to bone are rarely ever curable. Biopsies to determine the origin of the tumour in cases like this are rarely done.{{citation needed|date=June 2021}}