Bone tumors can be classified as benign or malignant, with benign bone tumors being relatively common and malignant bone tumors being less common. Bone tumors can be classified as either primary benign or malignant bone tumors that originate in the bone itself, or metastatic tumors that originate in a part of the body (e.g., from the breast or prostate) and then metastasize to the bone. Most malignant bone tumors in children are primary, while most malignant bone tumors in adults are metastatic. Bone pain is a common symptom of bone tumors, and a mass may be found. Some malignant bone tumors cause osteolytic destruction that weakens the bone and causes fractures with little or no external force (pathologic fractures). If there is persistent joint or limb pain, an x-ray is required. CT and MRI can show the exact location and size of the tumor, but often do not provide a specific diagnosis. Often, a biopsy of the tumor tissue (viewed under a microscope) is necessary to confirm the diagnosis. Biopsy samples can be obtained by inserting a needle into the tumor tissue (needle aspiration biopsy), or sufficient samples can be obtained through surgical procedures (open biopsy). Bone tumors should be treated promptly, including a combination of chemotherapy, surgery, and radiation therapy, which is particularly important for malignant tumors. Overview [Definition] Any tumor that occurs within the bone or originates from various bone tissue components, whether primary, secondary or metastatic, is collectively referred to as a bone tumor. [The incidence is slightly higher in males than females, and primary benign tumors are more common than malignant ones. Benign tumors are mostly osteochondroma and chondrosarcoma, while malignant tumors are mostly osteosarcoma and chondrosarcoma. [Clinical manifestations] Bone tumors are often found after injury, because injury can promote early detection of pre-existing tumors, but injury will not cause tumors. Common symptoms and signs are: 1. pain and pressure pain is the most common symptom of rapidly growing tumor, mainly due to tension or pressure of tumor on sensitive endosteal and eposteal membranes, but pain does not necessarily indicate that the tumor is malignant. 2.Local lump and swelling Benign tumor lump is solid without pressure pain; malignant tumor mostly shows diffuse swelling, rapid development of lump and obvious pressure pain. 3.Dysfunction Tumors adjacent to joints may cause dysfunction of joint activities due to pain and swelling. 4.Pathological fracture Both benign and malignant bone tumors can occur. Minor trauma can cause pathological orthopedics, which is the first symptom of some bone tumor patients and a common complication of malignant bone tumor and bone metastasis cancer. [Diagnosis] The diagnosis of bone tumor must be a combination of clinical manifestation, X-ray image and pathological examination, and biochemical determination is also a necessary auxiliary examination. 1. X-ray performance Benign bone tumor has the characteristics of clear boundary, uniform density, and generally no soft tissue and periosteal reaction shadow; malignant bone tumor is dominated by bone destruction, uneven density, unclear boundary, and irregular shadow in soft tissue. Malignant bone tumor should be routinely taken chest X-ray to understand whether there is tumor metastasis. 2.CT and magnetic resonance imaging (MRI) can provide a basis for the existence of bone tumor and determine the nature of bone tumor, also can understand the scope of tumor more clearly, identify the extent of tumor invasion of bone marrow and soft tissues, the relationship with adjacent tissues and organs, help to formulate the surgical plan and the scope of surgical resection, and can evaluate the treatment effect. 3.Pathological examination It can be divided into two kinds: incisional biopsy and puncture biopsy, which is the only reliable examination to determine the diagnosis of bone tumor. 4.Biochemical measurement Malignant bone tumor should be measured by blood calcium, blood phosphorus, alkaline phosphatase and other biochemical indexes, where extensive osteolytic lesions blood calcium is often elevated, serum phosphatase reflects osteogenic activity, osteogenic tumors such as osteosarcoma have significantly elevated. [Surgical staging] The pathological grading of tumor reflects the biological behavior and aggressiveness of tumor. The use of surgical staging to guide the treatment of bone tumors has been recognized as a reasonable and effective measure. Surgical staging is a combination of surgical grading (grade,G), surgical region (territory,T) and regional or distant metastasis (metastasis,M) for comprehensive evaluation to develop surgical plan. Surgical grading determines changes in clinical presentation, imaging features, histological patterns and laboratory tests, and is divided into three levels: G0 is benign, G1 is low-grade malignant and G2 is highly malignant. Surgical area T is the extent of tumor invasion, bounded by tumor capsule and interstitial compartment T0 is intracapsular; T1 is extracapsular but within the interstitial compartment; T2 is extracapsular and extrainterstitial compartment. M is metastasis. m0 is no metastasis, M1 is metastasis. [Treatment] Treatment of bone tumor should be based on surgical treatment, combined with preoperative and postoperative chemotherapy, radiotherapy, immunotherapy, traditional Chinese medicine and other combined treatment methods, firstly consider preserving the limb and removing the tumor as much as possible, while putting amputation in a prudent position. Different treatment methods are adopted according to the nature of tumor, site of onset, extent of infiltration and whether there is metastasis or not. Commonly used surgical methods are: (1) Scraping and bone grafting: the diseased tissues are thoroughly scraped and cleaned, and the bone cavity wall is coated with alcohol, carbolic acid or zinc chloride to eliminate residual tumor cells and prevent recurrence, and then bone grafting is performed to fill the bone defect area. It is suitable for osteolytic or mixed benign lesions, such as bone cyst, endogenous chondroma, benign bone giant cell tumor, etc. (2) Resection: complete removal of the tumor at healthy bone. It is suitable for benign tumors with osteogenic intra- or extra-osseous growths, such as osteoma, osteochondroma, etc. (3) Amputation: A section of bone where the tumor is located is amputated together with the intact tumor, and the defective area is replaced with allograft hemi-joint graft or artificial joint. It is suitable for benign tumor infiltration or low-grade malignant tumor (such as grade II giant cell tumor of bone). (4) Amputation or arthrodesis: Applicable to malignant bone tumors. Malignant tumors in the lower end of long tubular bones require high amputation, while the upper end is subject to arthrodesis. Benign bone tumor Osteochondroma (exophytic bone warts of osteochondral bone) is the most common benign bone tumor, mostly seen in people aged 10 to 20. This tumor often grows on the surface of the bone and forms a mass that protrudes outward. Patients may have one or more osteochondromas. Multiple osteochondromatosis is usually familial. About 10% of patients with multiple osteochondromas may develop a malignant transformation called osteochondrosarcoma. Solitary osteochondromas do not usually progress to osteochondrosarcoma. Benign chondrosarcoma usually grows in the center of the bone (i.e., within the bone marrow cavity) and develops between the ages of 10 and 30. They are often found incidentally on x-ray for other reasons, and the diagnosis can be made based on the features on the x-ray alone. If the chondrosarcoma does not cause pain, surgery or other treatment is not necessary, but periodic radiographs are needed to monitor changes in size. If the tumor remains undiagnosed or painful after radiographs, a biopsy is required to determine whether it is benign or malignant. Chondroblastoma is a rare bone tumor that grows in the epiphysis, most often in people between the ages of 10 and 20, and can cause pain. Treatment includes surgical excision, and occasionally the tumor may recur after surgery. Mucinous fibroma of cartilage is a rare tumor that occurs in people under 30 years of age and often causes pain. The tumor shows specificity on x-ray. Treatment includes surgical excision. Osteoid osteoma is a small tumor that occurs in the long tubular bones of the extremities, but can also occur in other bones. It usually causes pain that worsens at night and is relieved by small doses of aspirin. Sometimes the muscles surrounding the tumor may atrophy, which improves after the tumor is removed. Bone scans with radiotracers, CT or special X-rays can help identify the tumor site. Surgery to remove the tumor is the only way to permanently eliminate the pain. If the patient does not want surgery, aspirin may be taken to relieve symptoms. The age of onset of giant cell tumor of bone is usually 20 to 30 years old. The tumor often originates in the epiphysis and extends into the adjacent tissues. It can cause pain. Treatment depends on the size of the tumor. Small bone defects can be filled with bone graft or bone cement. Sometimes the tumor is so large that a section of bone is removed. About 10% of tumors may recur after surgery. The tumor rarely becomes malignant. Primary malignant bone tumors Multiple myeloma is the most common malignant bone tumor that originates from the bone marrow cells that produce hematopoietic cells (see Section 159) and is most common in the elderly. It can involve one or more bones, so pain can occur in one or more places. Treatment is complex and includes chemotherapy, radiation therapy, and surgery. Osteosarcoma (osteogenic sarcoma) is the second most common type of malignant bone tumor. Although the age of onset is usually 10 to 20 years, it can occur at any age. Older adults with osteomalacia deformans sometimes develop this tumor. About half of the tumors occur around the knee joint, but they can also occur in any bone. The tumor can cause pain and swelling of the limb. A biopsy can help confirm the diagnosis. Osteosarcoma requires a combination of chemotherapy and surgery. Chemotherapy is usually followed by surgery, and pain may be relieved during chemotherapy. About 75% of patients survive for at least 5 years after diagnosis. In the past, amputation was usually required, but with advances in medical technology, limb-sparing surgery is now possible. Fibrosarcoma and malignant fibrous histiocytoma are essentially the same as osteosarcoma in terms of clinical presentation, site of origin and treatment. Chondrosarcoma is a malignant tumor of cartilage. Many chondrosarcomas are slow-growing and low-grade malignant tumors that can be cured by surgery, while others are highly malignant and have a tendency to spread. A biopsy can help confirm the diagnosis. Chondrosarcoma must be completely removed at the time of surgery, as it is not sensitive to either radiation or chemotherapy. Amputation is usually unnecessary. If the tumor is completely removed, more than 75% of patients will survive. Ewing’s sarcoma (Ewing’s sarcoma) is more common in males than females and occurs at the age of 10 to 20 years. Pain and swelling are common symptoms. The tumor can sometimes grow very large and reach the entire length of the bone. Although CT and MRI can determine the size of the tumor, biopsy is still necessary to confirm the diagnosis. Treatment includes combination surgery, radiation and chemotherapy. Over 60% of patients are cured by treatment. Malignant lymphoma of bone (reticulocytic sarcoma) most often develops between the ages of 40 and 50. It can originate in any bone or part of the body and metastasize to bone. The tumor often causes pain and swelling, and the destroyed bone is prone to pathologic fractures. Treatment includes combined radiotherapy and chemotherapy and is as effective as surgical resection. Amputation of the limb is usually not required. Metastatic bone tumors Metastatic bone tumors are malignant tumors that have metastasized to the bone from a primary site in the body. The most likely malignancies to metastasize to bone are breast, lung, kidney, and thyroid cancers. Cancer can spread to any bone but usually does not spread beyond the elbow and below the knee. X-rays and radiotracer bone scans can determine the location of the tumor. Sometimes, metastatic bone tumors develop symptoms before the primary site. Symptoms may include pain or bone destruction and fractures due to tumor infiltration. A biopsy can help localize the primary site. Treatment options depend on the type of tumor. Some tumors are sensitive to chemotherapy, others to radiation therapy, and some are sensitive to both radiation and chemotherapy or neither. Surgery can enhance bone stability and help prevent fractures.