Sarcoma and bone oncology

Bone tissue tumors are divided into benign and malignant, and they are also primary (growing directly from bone structures) and secondary (metastases of other malignant tumors into bones).

Among benign tumors of bone tissue, the most common are:

• Aneurysmal bone cyst is a gradually enlarging mass that usually appears before the age of 25 . This is a cystic lesion that develops, as a rule, in metaphyses of long tubular bones. Symptoms include pain and local swelling. The most successful treatment method is surgical removal of the entire affected area.
• Benign giant cell tumor of the bone – most often affects people aged 20-30 , such malformations occur in epiphyses and distal metaphyseal-epiphyseal regions. These tumors are considered locally destructive. They continue to grow, destroying bone, can eventually destroy all bone tissue and spread to soft tissues. Such tumors often recur after treatment.
  In isolated cases, a bone giant cell tumor can metastasize to lungs. A biopsy is required to confirm the diagnosis. Treatment is complex, often with immunobiological drugs application.
• Chondroblastoma is a rare tumor that most often develops in people aged 10 to 20 years . Arising in epiphysis, it can grow and destroy bone and adjacent joint. Tumor is removed surgically. Frequency of local recurrence is from 10 to 20%.
• Chondromyxoid fibroma is very rare and usually occurs before the age of 30. The proximal part of tibia and wing of ilium are typical locations. After biopsy, chondromyxoid fibroma treatment consists of surgical excision or curettage and bone grafting.
• Enchondroma can occur at any age, but is more common in people aged 10 to 40 years . They are usually located in metaphyseal diaphyseal region inside bone marrow canal. These tumors are usually asymptomatic, but can grow and cause pain. They are often found accidentally during X-ray examinations performed for other reasons.
  Asymptomatic enchondroma does not require biopsy, removal, or other treatment, but a differential diagnosis with rare but malignant tumor chondrosarcoma is required.
• Non-ossifying fibroma ((fibrous cortical defect, fibroxanthoma)is bone benign fibrous neoplasm. They usually occur in metaphyses area, especially often in thigh distal part, in distal and proximal parts of tibia. They can progressively increase and become multifocal. Small non-ossifying fibroids are asymptomatic. However, when about 50% of bone diameter is involved, pain appears and risk of pathological fractures increases.
  
  Non-ossifying fibroids are usually discovered accidentally during instrumental examination (for example, after injury). Small non-ossifying fibroids do not require treatment, but patient should be monitored. Defects that cause pain and are more than 50% of bone diameter are an indication for removal and bone transplantation, which allows to reduce pathological fracture risks.
• Osteoid osteoma is most common in young people (usually between the ages of 10 and 35) in long bones, but can occur in any bone of skeleton. Characteristic pains that usually worsen at night. CT or MRI, which are the most informative diagnostic methods are performing. Ablation of pathological focus within a small zone using transcutaneous radiofrequency energy in most cases gives favorable results. Rarely, these tumors are removed surgically.
• Osteoblastoma is a rare benign tumor that consists of tissue histologically similar to osteoid osteoma. Osteoblastoma is much more common in men, usually between the ages of 10 and 35.
  

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  Tumor develops in bones of spine, lower leg, hands and feet. It is a slow-growing tumor that has ability to destroy normal bone. Visualization is carried out by conventional radiography, CT and MRI. Usually, an open biopsy serves as basis for making an accurate diagnosis. Treatment requires surgical intervention.
• Osteochondroma is the most common benign bone tumor with possible localization in any bone, but most often in long bones epiphyses.
  

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  Most often, they occur in people aged 10 to 20 years , they are both single and multiple. There is a family predisposition to multiple osteochondromas development. Removal is conducted if tumor compresses a large nerve or vessel, causes pain, disrupts growth, or has a destructive appearance on imaging, suggesting a malignant chondrosarcoma.
• Osteoma is an area of uniformly dense bone that is benign. They are most common in skull bone and area around nasal bones and are rarely found in axial skeleton or pelvis. Small osteomas are called bone islands. They are not painful and are often found accidentally on an X-ray.
  Diagnosis is established on basis of X-ray examination data. In case of doubtful diagnosis, an MRI study will help. Osteomas do not require a biopsy.
  
  

Among malignant tumors of bone tissue , the most common are:

• Multiple myeloma is the most common primary malignant bone tumor, but is often considered a tumor of bone marrow cells within bone rather than a primary bone tumor because it is of hematopoietic origin. Even if multiple myeloma is considered a hematologic tumor, detected skeletal abnormality must be differentiated from other bone tumors. Multiple myeloma occurs mainly in older people. Bone changes are well treated with radiation therapy.
• Osteosarcoma (osteogenic sarcoma)is the most common malignant primary bone tumor (if myeloma considers bone marrow cells tumor rather than a primary bone tumor) and is highly aggressive. It most often occurs between the ages of 10 and 25 , although it can develop at any age. There is a genetic predisposition, especially in children who are carriers of hereditary retinoblastoma gene (RB1 gene variants)and Li-Fraumeni syndrome (TP53 gene).
  Osteosarcoma produces malignant osteoid (immature bone) from tumor bone cells. It usually develops in knee joint region (in thigh distal part more often than in tibia proximal part) or in other long bones, especially in metaphyseal-diaphyseal region and can metastasize, usually in lungs or other bones.
  Typical symptoms are pain and swelling in the affected area.
• Adamantinoma – occurs rarely (<1% of malignant bone tumors) and most often develops in lower leg. Usually, tumor affects teenagers and people in their 20s , but it can be registered at any age. Adamantinoma develops slowly and in most cases manifests itself in form of pain and local swelling. Metastasis can occur, mainly in lungs, but is quite rare. Adamantinoma treatment consists in its large resection and bone defect restoration. In some cases, amputation is performed.
• Chondrosarcoma is a malignant tumor of cartilage tissue. They differ from osteosarcoma in a clinical view point, therapeutic methods and prognostic factors. 90% of all chondrosarcomas are primary.
  Chondrosarcomas most often appear in elderly. They often develop in flat bones (for example, pelvis, scapula), but can develop in any part of any bone (among long bones, femur and humerus are most often affected).
• Chordoma is a rare tumor that develops from remnants of embryonic chord. This tumor is most often localized in spine end sections, usually in area of sacrum or near skull base.
  Chordoma of sacrococcygeal region causes almost constant pain. With a chordoma at skull base, symptoms of damage to cranial nerves, more often oculomotor nerves, are possible.
  Symptoms of chordoma can appear for months or even years before a diagnosis is made. If tumor is located in sacrococcygeal area, radical removal is often possible. Skull base chordomas are usually not amenable to removal, but may respond to radiation therapy.
• Ewing's sarcoma of bone is a bone tumor represented by small, round malignant cells, with a peak incidence between 10 and 20 years of age . It mainly affects limbs bones, although it can be noted in any other bones. Ewing's sarcoma tends to spread significantly, sometimes involving the entire bone. The most common symptoms are pain and swelling in affected area. Tumor treatment includes various combinations of surgery, chemotherapy, and radiation therapy.
• Fibrosarcoma and undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma of bone) – these tumors are similar in characteristics to osteosarcomas, but produce fibrous tumor cells, affect the same age group, and cause similar problems. Treatment and outcome for marked changes are similar to those for osteosarcoma.
• Lymphoma of bone (formerly known as reticulosarcoma) affects adults, usually between the ages of 40 and 50. As a rule, this is a diffuse large B-cell lymphoma. It can occur in any bone. It can develop as a primary bone tumor, in combination with similar tumors of other tissues, or as a metastasis of a known lymphoproliferative disease.
  Pain and swelling are common symptoms of bone lymphoma. Pathological bone fractures are also common. Bone lymphomas are usually treated with systemic chemotherapy.
• Malignant giant cell tumor is rare and is usually localized at the end of one of skeleton long bones. A malignant giant cell tumor that developed from a previous benign giant cell tumor is characterized by resistance to radiation therapy. MRI and biopsy are performed to establish the diagnosis. Treatment of malignant giant cell tumor is the same as for osteosarcoma.
• Metastatic bone lesions are 100 times more common than primary malignant lesions. Any malignant tumor can metastasize to bones, but most often this happens with cancer of breast, lungs, prostate, kidneys, thyroid gland, colon. Metastases are manifested by pain in bones, although they may remain asymptomatic for some time. Symptoms of bone metastases may appear earlier than clinical manifestations of primary tumor, or develop in patients with an established diagnosis of malignant neoplasm.